Those aircraft all had the big round dial of yesteryear! Careful now, you're supporting my hypothesis!
I assume you're speaking of the "standby" instruments, which (at least on the 757/767) the pilots are trained to use ONLY if the glass PFD failed, and they are not exactly "big". I suspect most flight crews seldom if ever look at the standby instruments (especially during a 'high workload' situation such as landing) (BTW, the 777 has round dial 'standby' instruments, granted they are LCD displays and not real round gauges - Asian apparently didn't look at those either). We had a problem back around 1990 with the 767 standby instruments blanking - and they were in service something like 9 months before we got the FIRST squawk (and that from a Boeing flight test pilot)
As for the size of the speed tape display on the 777 being "tiny", the speed tape takes up ~8 sq. inches on the PFD. That's the same area of a 3.2" diameter round dial, and the digital reading is nearly a square inch - several times the size of the digital reading on a typical 3" round dial.