As in, "can they do it" or "will they do it"? Two very different questions. I'd say about half the players I know wouldn't play a new simple board game if they had to read the rules to do it. If you sit down and explain it to them? All over it.
I'm the designated rules guy in my circle. New game? They hand me the rulebook and wander off. "Let me know when you figure it out". It'd drive me nuts if I weren't going to do it anyway...
But the thing I rather like about RPGs (in general) is that the GM needs to know the rules, but by and large, the players don't. They can just ask, "I want to sneak around that guy and stab him in the butt. Can I do that?"
GM goes, "yeah, let's roll your sneak and compare it to their perception, carry the one, mercury is in retrograde, this is a year divisible by 4 but not 100, and... sure, you can do that. Roll that big die. Normally, you need a 12 to succeed but you have a broken foot, so you have a -2 to..."
"Nobody cares, I got a 17. Did I win?"
The rules being written conversationally is an impediment for them. How'd you like, say, a set of instructions on how to put together a large piece of furniture that were 4 or 5 times as long as necessary and had more artistic pictures than useful drawings?
I think there is an art to writing a good rulebook - an art that a lot of publishers haven't quite figured out. Like, the 5e D&D rules are pretty poor. There's relevant rules spread throughout multiple sections. Not to mention that the rules are split out over three core books, with the GM Guide being mostly optional, except for the ten pages or so that aren't. And I've always considered monster manuals a flawed concept that has rarely been done well. An alphabetical monster phonebook is an awful way to organize an adventure.
Rulebooks should tell a story of how to play. They should fill your imagination with use cases. When you read about downtime activities, you should have a picture in your head of a character coming back from adventuring, shopping at stores, crafting, watching puppet shows, or whatever. When you read through character creation, your brain should be exploding with character concepts you want to try. When you read "give your class stat a +4 modifier in box 12a", it doesn't really pop, you know?
I think the best RPG I've read was West End Games' Star Wars RPG. It's been years - decades - since I gave it a full read, but when I got rid of all my RPG stuff as a kid, that RPG (along with the Miniature Battles sourcebooks) is all I kept. I've dumped more recent Star Wars RPGs (Wizards' Saga edition sucked and FFG's has a fine system, but the books themselves suck), but I'll never get rid of my WEG one.