The thing about 'you can hack the game to remove that problem' arguments is, well, *can* you do that?
Not every game is equally easy to modify, for various reasons.

Perhaps the game is tightly balanced around a particular gameplay loop and pacing, and things go wonky if you fiddle with that.

Perhaps the maths behind the game is precise but also inscrutable, so making things that fit with it is tricky.

Perhaps the play-culture for the game prioritises canon and Rules-As-Written, and hacking is seen as outside the expected scope of the game.

Perhaps the game has several interlocking subsystems that feed back into each other, and breaking one breaks the rest too.

And, this works the other way too.

Perhaps the game is intentionally modular, so you can swap things in and out without affecting the rest of the system.

Perhaps the game uses rules-over-rulings and improvisation and judgement calls, and the mechanical framework is kept loose.

Perhaps the game doesn't really care about balance, because the degree of randomness and rapid turnover of PCs means it all averages out in the end.

Perhaps the game provides explicit guidelines on why it was made the way it was, and suggestions on how to hack it well.

Perhaps the culture surrounding the game is built on homebrew and customisation and the game *expects* you to hack it.

Perhaps the game's framework is light enough that you can tinker with it without affecting a tight gameplay loop.

So, that's a distinction you gotta consider when invoking 'but you can hack it'.
Like, if I take pathfinder 2e as an example, that game has a tight combat loop that's carefully balanced to produce a particular experience, and all the various options are built around that.

Designing homebrew for pathfinder 2e is tricky. It involves maths and studying the classes and how they click together. It's a big task.

By comparison, let's take a game like the GLoG. It's modular, rules-light, with guidelines for hacking it. It's flexible. So, no wonder there's a huge homebrew scene for GLoG content; that's what the system is *made for*.

In conclusion; there are games that are tight and inscrutible and complicated, and there are games that are loose and modular. "You can hack the game to do whatever" is only really a practical argument when applied to the second type.

For the first type, whilst it's technically possible to hack problems out, it's not really reasonable to expect people to do that because of how much work it takes to do that and get a game that's still, like, functional and recognisable as the game you started with.

as an addendum: I'm not saying one type of design is better than the other. I love a tight, precise engine that does exactly what it sets out to, but I also love games that invite you to tinker and experiment with them. Both have a place.

addendum 2: I don't know where 5e falls on this scale, I've never bothered trying to homebrew for it and barely played it.