He's talking from an emotional place. Flash Thompson died in 1974 and obviously he was someone Cap wasn't able to save. Man this comic is just layered and suggestive.
Historically, implementing technology without the proper social and political conditions in place, doesn't exactly work. Like someone called Hero of Alexandria invented the Steam Engine or some version of it back in Roman times but that didn't create an industrial revolution because of the political and economic conditions in place there not being sufficient to exploit it. During the Cold War, the USSR actually made a lot of innovations across the board, many of them before USA did but couldn't implement it because of totalitarian society and so on.
In our real world, you have tech companies forming a consortium that decides on standards of lightbulbs and other tech and they make sure that it decays so as to sell more bulbs. That happened with old bulbs and with modern LED even if technologically you can make lightbulbs that last, theoretically, forever. This is called (
https://en.wikipedia.org/wiki/Planne...and_supporters). It happens because of economic reasons not scientific ones. (
https://www.newyorker.com/business/c...-built-to-last) This article put its right, "Economics, not physics." So it's paradoxically enough, not unbelievable for Reed's tech and stuff to be kept in the basement or something, or used for top secret bleeding edge exploration only. The only way you can actually go all the way is if physicians and tech inventors got involved in politics and in real life most of those guys are too busy doing the science to get involved in politics and stuff. In a superhero story, the question becomes, do I take over the world to make a better tomorrow.
People have pointed out that we are technologically capable of ending poverty, providing food for the whole planet, and helping people but politics and social norms and so on prevent those problems from being solved. Climate change is this great threat to everything that scientifically we need to solve but implementing those changes needs political will and interest which is again behind the science.
So that's why you ain't getting your jetpack.