May well be the power supply that goes bad in those old machines. If the capacitors were selected with too tight voltage margins then a degraded supply turned on decades later could push them out of spec.

I had a look at the Intel 740, where it looks like their own manufactured boards used 25 V tantalums for 22 uF, Diamond used 20 V for the same, and some more obscure brand had 16 V. Right now 25 V tantalums can be about twice the price of 16 V, so you would've needed a good reason or deal to use them. Could be availability, but smaller manufacturers seem to have been able to ship boards with lower-rated parts.