That's entirely logical, but the in-game result is either:That is still faulty logic.
A wood elf with a twisted leg would still have more dexterous hands than a baseline human or be more dexterous than a human with a similar condition. And a dwarven circus performer would still be a dwarf and thus not as dexterous than a elven performer with similar background. But he would have better endurance.
Being a circus performer does not change your biology.
1. The mechanical difference is too small to care, so you have a +1 dex but it doesn't affect rolls and elves don't actually feel more dexterous, or
2. The difference is important, so people only play dexterity classes as elves and endurance classes as dwarves (ie there would never be a dwarf acrobat) not because it's illegal but because you're just going to be bad at you job which is bad for the team, or
3. the difference is big enough to be noticeable to some people and not to others, so some people have reaction 1 and some have reaction 2. This is what 5e does.
If the dex bonus isn't enough to make everyone think it's stupid to play a dwarf archer, it isn't consistently informing the fiction.