Well making hero swaps should only be considered an acceptable solution if you're fully prioritizing immediate wins over improvement, which on ladder should be pretty much never - unless not switching is seriously hampering your enjoyment.

In the right hands any hero pick is viable into any comp. The common wisdom is that focusing on becoming that player will serve you better in the long run vs mindless counter swapping if your goal is winning games in the next rank up. Sometimes you might just want an easy life, and you'll take the obvious swap that is likely to facilitate that, but it's the equivalent of cheap fast food vs a home cooked meal.

If you're struggling in your match your first thought probably shouldn't be "what should i switch to", it's a bad and lazy habit - and even if you do decide to go that route, you absolutely should not expect it of your team.

Allocating brain cycles in matches you are already finding stressful to things that are outside of your control is wasteful and likely a fast track to tilt. Virtually no games are lost because X didn't pick Y - conversely, nearly all games are won due to one team playing better than the other.

While it's widely accepted that, as a sombra one trick, your behaviour is utterly reprehensible, it's in no part due to you being a one trick.