NASA shackeled itself to Shuttle, a expensive failure of a project and from them on the basically didn't develop anything new for 3 decades.
The millitary if anything is where such thinking should have been happening. The went threw many iterations of rockets.
A few reasons why they never managed to go reusable. Reliance on solid boosters, once you have them reusability is not really practical.
The millitary also simply doesnt care much about cost. What they care about is reliability above all else.
And you would be suprised how much engineers buy into constraints. The reality is that after a while the status quo of the industry you work on is simply an assumed constraint. Nobody asked engineers the question 'how do you get 100 tons to orbit per week' or whatever.
As Musk puts it, the most difficult part is asking the right question. Nothing is as harmful as smart engineers spending lots of money and time answering the wrong question.