One needs to make a distinction between "old tech", and "useless old tech".
(MS)DOS is an extremely powerful, very viable operating system used in far more places---and important places, at that---than you might imagine.
Not making any judgements, mind you, but your sentiments sound perilously close to those of millennials (Gen-X/Y/Z-ers)whose mantra is, "if it's not the newest, it can't be any good." But, seeing as how you have the extremely good judgement to be a reader of this venue, I'm sure this doesn't apply to you.
Oh, and by the way---I'm sure you've heard of that 60++ year-old system called COBOL, 50+ y.o. language called FORTRAN, and 40-something y.o. system called UNIX.
There are really great applications and uses for (MS)DOS. You simply haven't found them yet...nor encountered them.