What do we gain by waiting?
The act of delaying newer era classes dooms them to mediocrity, by ensuring that the age-group of people most attached to the era are "off the curve" of active participation.
I get the "VMX was originally created for short travel bikes" argument, but its no coincidence that VMX was at its strongest when the bikes were ~20 years old: the people with a passion for the pre-75 era were ~40, and were in that happy window of (most people) being financially stable, having family stuff under control, and still young/fit/enthusiastic enough to go racing.
The time for pre-95 is now.
Pre-75 was started at the ideal time to maximise its potential.
Pre-80/Evo snuck in, just in time.
Pre-70 was left a bit too late.
We left pre-85 too late.
We left pre-78 too way late.
We left pre-90 too late.
These classes will NEVER reach "their full potential" because we never gave them a proper chance.
If we leave pre-95 too late, then it will be doomed to mediocrity as well - and it will never be able to help support pre-90 and the older eras.