It wouldn't necessarily be so easy to replace the mechanical switches, with mass produced (general purpose), electronics.
Because the up/down buttons, would need debouncing circuitry, be able to cope with a huge range of logic voltages (from really low, to high, e.g. 3.3V, 5V, ECL, very low V, etc).
If the item was battery operated then mechanical digits, would consume zero power. But bright led displays (to show the switch positions), would probably consume a fair bit.
Quality push switches, get high prices as well, which it would still need.
Also if there are already other led displays in the item. Having even more for the input switches (hex), may be too over-powering.
The modern solution, seems to be LCD screens. But the cheap, dot matrix (such as 2 lines by 16 character) ones, seem to be NOT very clear (in MY opinion). The contrast is usually NOT very good, and they tend to be too small, to easily read. E.g. Compare simple calculators, with relatively good/readable LCDs, with programmable, 2 x 16 char, calculators. The LCD screen (sometimes graphical, as well), is usually of somewhat poor (unreadable), quality, in my experience.
The final button set, I showed above, are VERY usable, WITHOUT a stick. But then, I assume, you will be some distance from your rack computer. So it could be different, for you.
The keyboards (in my experience), from the 1960's .. 1980's, were of much better quality, than the modern (membrane/cheap) ones. They had a substantial, quality/solid feel to them. (But I guess poor quality ones, were available, then, maybe).
Probably the reed relay ones, made nice/quality keyboards, when they use to commonly do keyboards, that way.
BUT you still can get quality, mechanical keyboards, such as Cherry (PC). So things are not too bad.