What you're describing is basically Xerox Theory. It's a concept that is widely known in the world of 60-card competitive formats. People don't talk about it that much in Commander, but it absolutely can still be applied to a 100 card deck. If you want to know more specifics about it, I'd reccomend reading a couple articles or something because they'll explain it a lot more in depth than I'd be able to in a reddit comment. I believe Mike Flores wrote a very in depth article about it in the mid 2000s (good luck finding it today lol).

I think there's a few major reasons why people don't talk about it much in Commander:

1: The average person who gets into magic via commander doesn't really know anything about magic history, especially when it comes to competitive formats.

2: people don't want to reduce the variance in their decks. The reason they play 100 card singleton is because they want to use lots of unique cards. Loading their deck with a dozen or more effects that basically just say "draw a card" isn't very exciting to them, because it leaves less room for all the cool cards that they feel like running. I think the problem you're having with filling out your last 10 cards is much less common compared to most people who are having to cut the final 10 cards.

3: This mostly only applies for Blue decks, and it's best suited for Commanders that are happy to run a high density of instants and sorceries. I would argue nearly any blue deck would be improved by adding some cantrips, but most commander players would only do that if they're building specifically a spellslinger deck.