If you've ever used a device with a WAIT line, you know that the system operates at full speed unless something causes it to slow down.
OK, I realized that just after I posted

The wait line is an invention from the days when technology did not allow "speed across the board" and you tried to squeeze as much as possible out of existing technology, which may still be the case for multigigahertz systems. However, today, there is no problem getting stuff that coexist with a 100MHz one-clock '51 without a wait line, so the decision to omit the wait line is, in my opinion, sound.

If you follow the progression of '51 derivatives, you will see that, pretty much, the '51 has progressed in lockstep with the chips you use with it. E.g. I recall no '51 faster than the "standard" memory chip of it's day. I remember buying 200nS RAM and, today, 12nS is pretty much a comodity.

Now, if you want to use antiques from the days when 10 MHz was a speed demon (remember the PC-AT) together with devices designed to work with todays technology, then you have a mismatch and that is what, in marriage, lead to divorce. Why should a mismatch in electronics not lead to a divorce?

Erik