There are approximately 90 million heads of domestic cattle in the US. That right there will tell you that wild bison herds wouldn't even be close to enough to replace modern beef production, even at 60 million.
No one really knows how many bison there were in pre-Columbian times. 50% more than estimated, is not a big difference, especially since our confidence intervals are very, very wide about historical numbers. That being said, there's no going back to the 1400s. Farming and ranching are here to stay.
A lot of these are dairy cows too which changes the calculation
Almost all dairy cows get turned into meat for humans after their milk production drops.
Most food sources are more efficiently produced through deliberate agriculture rather than just letting them grow wild.