Well, I did have a personal experience with it playing in a 5e campaign a couple of years ago. The DM's home-brew Knight class, which I took, wound up being massively underperforming. Funny thing is, when I complained about it, no one believed me. It was all in my head. It wasn't really happening.
So, I tracked damage output for the group, per PC, for a couple of sessions. Wound up that out of 5 PC's, the only one who did less damage than me was the enchanter wizard who had almost no direct damage spells. And, it wasn't even close. The paladin, with the same sword and board fighting style as my fighter, was doubling my damage. Everyone else was triple or higher.
Now, at that point, yeah, I managed to convince my DM that some changes were needed to be made.
OTOH, when my Forge Priest was way under damaging, I didn't care. That's not what the character was for. He was all about healing and making stuff. No problems. So, it obviously depends on the expectations of the player for the character.
Heh, we had a player who massively min-maxed, didn't care about anything else, completely lose his naughty word when the big bad fight turned into a ranged, running combat and his great axe wielding maniac was pretty much riding the pines. Explaining that it was his own fault for creating a one trick pony character did not help the conversation.
He actually left the group over it.
So yeah, it can matter a lot and players can react in very different ways.