My shop fixtures are all scavenged from many locations over many years. I replaced some of the ballasts over the years. When the LED replacements came along, the fixtures were $45 each at Costco and the substitute bulbs were about $8 each. I bought a pallet of them at an auction for about a $1 each and they were plug and play. When the fluorescent bulbs died I just switched to LED's.
But the fixtures are much cheaper now and you are correct, it no longer makes much sense to modify the fixtures, except that sometimes it's easier to do a little work on the existing fixture than to take it down and install another.
I see new utility "fixtures" that are little more than a tube with a cord hanging on the end. You put up a few clips, snap in the bulbs and plug them into a switched outlet or wire them into existing boxes.