That's largely what matchmaking aims to solve, assuming you have enough players you can get a reasonably balanced match to drop people into.

Bots can teach basics, but many of these games rely on abusing game mechanics in ways the developers didn't think of in development so it's impossible to teach. Or things are physically difficult to pull off.

Movement shooters especially have this problem because a core part of the game is abusing the movement system and abilities to out maneuver other players. You can explain the how, but executing it all automatically is a real skill that requires practice. I adore Titanfall 2. I sunk hundreds of hours into it. It's really something else when you get the movement down, it all happens so fast you can't think about it you just have to do it. There's no way to teach that with a tutorial, it's muscle memory and perseverance.

Titanfall 2 has all of these things, campaign, skirmish with bots and PvE, but the skill floor and ceiling is still brutal. Whether it failed or not is a question of how long you expected the game to last, but it still succumbed to the same fate. The more experienced players pulled the ladder up behind them and the matchmaker didn't have enough players to give everyone a fair match.