I'm not sure I'd go that far, but the reverse is certainly true: get the underlying architecture wrong and all the subsequent effort in the world won't give a usable product.
I have no idea how a really fast, efficient, usable 'push & shove' routing algorithm works, and I certainly wouldn't have the first clue how to go about implementing one. But I know they exist, and that having a really good one is a bare minimum requirement for any serious layout package. It's what the board designer will be using 99% of the time once the board is placed and the DRC rules are set up, so it's got to be absolutely right. The underlying database structure has to be designed around that.
If it's not as fast, capable and reliable as the one in Allegro then I'm not interested, sorry.