Well, you see much more of those cheaper starter bows because much more new or newly converted shooters are frequenting 3D events.
A lot of veteran archers have no interest in 3D or even meeting with people.
Then there is a difference in how performance is measured: Put 6 arrows into a nice group with 150 fps or putting 6 arrows into a group with 190 fps with the same gpp. Now where is the performance difference? On the target or on the speed?
Put this in a real world situation: You thought your deer where closer than it really was and it drops when you shoot due to the string noise. The second bow will most likely still get a deadly hit, while the first one will get a bad hit or no hit at all.
If you draw longer or shorter, the cheaper production bows are most likely not the best choice for you. That's why they are production bows. They are built for the average (majority) size and parameters of the potential shooters.
Even with those vintage bows, there were better performers back then and other companies who marketed better.