Kinda. While it technically says "optional" in the PHB, I think the default assumption in most groups (especially of 'advanced' players who've played 3e and/or 4e) is that anything in the PHB is fair game.
That people assume something doesn't actually mean their assumption is correct. Especially not when their assumption is in direct conflict with presented evidence: in this case, the evidence is that the game has been designed so that feats are optional - not
technically optional, full-on have to pay for an expansion to the game to get them in the first place optional - and the designers have been clear about the intent that any optional rule is intended to be included only if those including it
like it.
If something is broken, just saying "you don't have to use it if you don't like it" doesn't fix the problem. Maybe I do like feats, but a few overpowered ones are wrecking the whole system. We could argue all night about how imbalanced the relevant feats are, but the fact is that a substantial part of the 'advanced' playerbase looks at GWM compared to, say, Tavern Brawler, and thinks that one is a must-have and the other is a piece of garbage. For them (regardless if they're "right"), it's not a choice. It's a tax. This isn't fun for them. And remember, this is the feat system's target audience.
I don't think that folks that want something from the feat system other than what it provides, by which I mean the ones that you describe as looking at Tavern Brawler (or any other feat) and thinking it is "a piece of garbage", are actually the target audience.
I also don't think that Great Weapon Master and Sharpshooter are actually as over-powered, must-have, and "tax" status as folks are claiming they are - of course, I've only got my own experiences with the system and my own players that have thus far found Actor, Weapon Master, Elemental Adept, Observant, and Dungeon Delver to be far more useful than the one player that has been interested in taking Great Weapon Master thinks the feat is in practical usage.
...some players, even ones who wouldn't normally be interested in feats, will look at GWM and feel like they have to take it, since it's so much more powerful than the ability bump.
I don't think the sort of players you are describing are anywhere near as common as they might seem on the internet, and at the very least, feeling like you are required to take some option that you don't actually like because it is mechanically better than other options,
but those other options are mechanically good enough that you do just fine if you take them instead, is completely on the player. No amount of game design can change a player from thinking that their is either "the best" or "garbage".
...Which is more about the balance issues of those particular feats than anything, but I believe putting always-powerful effects like GWM and SS in the same silo as situational effects (Actor, Charger, Skilled, etc.) is a recipe for trouble.
This illustrates that your expectation of the game differs from the expectation the designers have for it, because you just described a feat that only applies
in certain situations as being "always-powerful." The -5 to hit for +10 damage from Great Weapon Master is of as much use outside of combat as the advantage on checks to pass yourself off as a different person from Actor is in combat, which is to say basically no use because both feats (all feats, actually) are situational.
Yes, a lot of groups have a lot more frequent combat situations than other types of situations - but that's
their choice, so it's there use of the tools at hand, not the tools' design, that creates the problems they experience.
