The LSx motors have only been around for 10 years. Not 50.
The only thing they share with the original small block is bore spacing & overall size.
No overhead cam motor will make the torque that a pushrod motor makes. Pushrod motors will be around forever. They are cheap to build, less moving parts, and much cheaper to maintain/repair over a vehicle’s lifetime. Plus it is alot cheaper to do performance upgrades to.
I am not knocking the mod motor. I think it is a great motor. Doesn’t mean it is the best.