I think fundamentally every political side has the same broad goals (excluding the possibility Mr Trump is selling out America) of making America great and keeping it great, in whatever way you may think that means. The real difference between parties is implementation of policies to achieve those same goals.
I very much disagree with that Rporter. As the republican party moves further and further to the right the goals are becoming very much different.
As far as the idea of it taking a depression to get FDR's new deal legislation it's important to point out that FDR ran and got elected on an austerity platform.
FDR was moved to adopt left wing ideas on account of the pressure that was mounted on his administration from the left. Specifically the very important socialist and communist groups that existed at the time.
There is no left wing in politics today that can move any emergent FDR type, should one arrive, to the left. So long as we can't differentiate the rhetoric of the neoliberal new democrats from their right wing positioning it will be difficult to see where the pressure will come from to advance progressive policy.
I haven't seen it in my adult life time but I'm happy to be reminded.