Technology is the backbone of all development.
Technology allows human beings to augment themselves. It gives them better eyes, letting them see the microscopic world (microscopes) and the world so far away from us (telescopes). It replaces our arms and plows our fields (tractor) and builds our buildings (crane) for us. It frees up our time letting us think about things beyond simple survival: philosophy, ethics, justice, science.
And so it freed us from hard labor, but it also gave us actual freedom, liberty, equality.
Human beings are inherently limited. We can only run so fast and so far. We can only remember a tiny fraction of the knowledge we have accumulated and can only process a tiny fraction of all the calculations necessary for our development.
Because of this fact, once we reach our natural bounderies, we require technology to advance. We reached our natural bounderies hundreds of thousands of years ago, by the way.
To develop we needed counting systems and ways to record our memories on clay tablets. We needed to invent/discover(depending on your philosophical stance) mathematics.
And so any further development in any field must be aided by technology.
For some pratical examples:
We are currently nearing the end of science we can accomplish without smarter computers. Scientists are becoming increasingly more specialized because of this. Unlike what many seem to believe, we are not in the golden age of research, in fact we have been making less and less progress as time goes on.
We can't ever make faster computer hardware anymore because transistors are literally the size of a few atoms.
Not all hope is lost however, because of, you guessed it: technology. We are currently developing primitive AI's that can aid us in our scientific research and quantum computers that can go beyond current atomic limitations.
But your premise doesn't allow any of that. And in fact I don't even understand your premise. How can a society simply stagnate? Progess, sure. Regress, also sure. But stagnate?
In anycase, we really wouldn't be able to predict how your societies would "develop". Normally we track long-term social and cultural trends based on projected technology (increasingly intellegent AI, near total automation, etc...). But in this case we have no information. We have no backbone to work with. So... The best I can say is to take your pick of current ideologies and just say that's what your "future" society follows.