100k USD is about 90k EUR (and 77k GBP), which you may say doesn't change your point materially, but I'm not splitting hairs, that's more than a 10% difference.

I think people often put the goalposts further away than they truly are by comparing numbers cross-currency directly like this or just round numbers in general.

It is possibly to earn over £100k as a software engineer employee in the UK, however those tend to be very specialised fields. (Not all of them are finance related).

I do recall a software manager (OK apples to oranges) grumbling about 10 years ago about him exceeding that level, and having to play games to avoid being bit by the tax impact which cuts in between £100k and £125k.

That said, I do know engineers who indicate they earn in excess of £100k, and they're not lead nor founder level - just experienced in the appropriate area.