Moderate republicans and conservative democrats are *not* getting elected in droves. Not within mainstream parties, and not as independents - all the grass roots support is moving democrats further to "the left" and republicans further to "the right".
Conservative democrats and moderate republicans are *retiring* - even when they remain active in politics, because they care about their issues, they are not running tor re-election because they do not see near-future success as *elected representatives*.
There is no *flocking* of significant support for critical thinkers willing to put politics aside for results.
This is not a statement of party loyalty or inertia or whatever - it is an acknowledgement of facts. Party line voters are not the issue, the issue is the voters crossing across party lines or jumping out of the box are not voting for critical thinkers willing to work across the isle.
I wish that were the case, and hopefully that will be the case in the long term, but there is no electoral result or polling evidence anyone is "flocking" that way right now.