Yes this is true mostly because we as a country have become more and more disengaged from policy discussions and active participation in politics in general. This combined with older people being much more likely to vote and to vote conservative has led to the sort of multi-decade-incumbent ridden congress we have now.

This can pretty easily be solved by younger people voting more and enacting ranked choice voting. America is so cool because nothing (except maybe the bill of rights) is set in stone, we can change how it is!