If there is a Modern, there must be an Ancient and also a Future
Progress says that the Modern world is better than the Ancient. Can we also propose the Future will be better than the Modern? Progress would certainly suggest this, and the idea that the Future will be better than the Present is what motivates Progress today.
Progress is Altruistic
Will we live to see the Progress in the Future? Most of it no. First thing to observe then is that Progress is an altruistic act that our children and their descendants will benefit from. In the same way as Modern people believe they have benefited from the Past and enjoyed things their descendants made possible but never realised themselves.
An Endless Progress, Relativity and One Myth Of Progress
Will there be a point when we can't improve on things any more? In other words is human desire satiable? This question is more complex. People today are not happy until they have a mobile phone. A generation ago people were not unhappy with not having a yet-to-be-invented mobile phone. So desire changes, and Progress actually creates desires as much as it satisfies them. This is the essence of Economic Growth; to keep growing an economy must discover and create new markets and desires for people. This is obvious looking into the Past. In the Past people were satisfied with acquiring stone tools; it never crossed their mind they didn't have power tools. This is one of the key misunderstandings of Progress: people in the Past didn't want what we want. But it is argued that is because they didn't know about what would become available. Luckily Satisfaction is very trivially met. We can be happy with something like a precious gift for ages in ignorance of some fact that it was stolen. But were we to show stone age people power tools they would be instantly hooked because we can argue there is an unchanging law that people want to get things done easily. In the Past we got slaves now we get power tools. But then what to do with power tools? Ancient people would continue to make wattle and daub round-houses and live like they always did. Their culture and "ethnotechnology" would need to change for them to develop a taste for new things for example stone houses (odd that stone age people never lived in stone houses? -- it's cos they didn't have a concept of fixed territory so never settled in one place for long enough to make permanent settlement. That is a desire that has developed!). Desire and Progress are complex things. For this reason you can't actually say of people in the Past: they were impoverished compared with the Modern day. For this reason we don't need to view ourselves as impoverished compared with the Future. Each age defines its own goals and provides the means to achieve them. So while Progress may or may not be endless, it is irrelevant to the people of any age because they do not yet know what the Future holds and work within the confines of their own age.
Progress has an Evil Twin
If we argue that the people of the Past were poor and unhappy compared to ourselves, then we must also argue that we are poor and unhappy compared to the Future. To Proudly stand above the Past, is to be Proudly stood upon by the Future. This clearly isn't true. While we may work for a better future we are at the moment happy. Likewise our ancestors may have unwittingly worked toward a better future--discovering language, cooking, agriculture, wheels, maths, money, &c--but they were happy within their technology, knowledge and existence.
Absolute Progress
But there must be absolute desires that all people have. All people want to live and be healthy so medicine has to be an absolute Progress. That is true until we think again that in the Future people may not get old or die at all: how impoverished we and all our Modern progress now seems. When things becomes spread across an endless line of time they are relative and there is no absolute. If there is anything absolute we know that it isn't spread across time: it is true in each age. Progress by its nature s relative. Indeed the central argument of this blog post is that the relative is irrelevant, what we should seek the absolute.
Political Modernity
The story of things getting better also has a political element. Each ruler, in order to encourage support, has always rewritten history to make his predecessor seem vile, villainous, dishonourable and their times as ones of poverty and oppressive. Most famously when the Tudors took the English Royal lineage from the Plantagenets they completely rewrote history to make the mediaeval period seem one of abject poverty. This is a complete fiction. Mediaeval times were ones of great literacy, social cohesion and prosperity. They were of course blighted by the infamous plagues and ended with the bloody civil war (one of the most bloody conflicts on Earth) and came from the oppression of the Normans but compared with Tudor dictatorship people had considerably more freedom and self-determination. History however thinks of "Mediaeval" like Monty Python incorrectly records it in Search for Holy Grail (except for the Anarcho-Syndicalist Commune bit... Particularly if we think of Watt Tyler leading a revolution to overthrow the ruling elite in the C14th foreshadowing revolutions 400 years later.) Progress also inherits from Christian piety and evangelism being seen as a justification for political expansion to "undeveloped" or "primitive" (read Pagan) parts of the world. Flying the banner of "Progress" modern armies feel as justified as Religious Armies feel when on Holy War. It has a very dark underbelly justifying any amount of excess and brutality.
Meaning of Life is The Present

Conclusion
Yes Progress exists. Yes Modernity exists. But they are irrelevant to us because the basis of life, that which we must teach our descendants is to be happy with what they have got, to appreciate each day for it is all they have. If we teach that to the Future then the Future will be far richer than if we hand down the roots of a new ever changing technology. And in that we see the dissolution not of Monasteries this time but of the whole Modern Project. Finally Modern man can rest from chasing the carrot and join arms with the ancestors and their progeny to sit down and appreciate the simple fact of the world as it has been, as it is and as it will always be. Although the search for Progress is actually an illness that may indeed cost us not only our happiness but our world.