Sure, we could have had hacks that would have been faster to implement, but there isn't reason to believe it would have helped. The bottleneck was never in the code. Routers and OSes got v6 support ages ago and it's been working in lots of edu & gov networks all over the world for 20+ years. ISPs just haven't been enabling it.

Lukewarm deployment incentives for ISPs, lack of pull from device/app makers, etc have been the main problems. Apps adapted to the NAT world quickly, users forgot what capabilities they lost and started to fall into the NAT = security cognitive trap.