I think that actually helps. When I was an altar server we had 4-6 boys at Mass. The older boys did most of the work and the younger boys carried candles etc. until they learned how to do more. At my current parish we have just a couple of servers at each Mass and the young kids have to just muddle along as best they can. I think some kids now are intimidated about having to remember everything.
I think you’re right. With the old Mass there’s a certain discipline that goes along with serving as an altar boy. I’m always amazed at seeing the young boys - and I mean 7 or 8 years old - kneeling with ramrod straight backs while holding their hands perfectly together in prayer. You simply can’t find that sort of patience and discipline in kids today.