I thought it’s time to ask by now, just out of curiosity: If an EU citizen lived in the UK, met all the conditions for settled status, had a job, and a house, and for whatever stupid reason did not apply for settled status by June 2021, without any valid excuse, what would happen or would have happened to them in practice?
Would anyone check and ask them to leave, or would they be in trouble returning from a holiday abroad, or would this go undetected (for a person who needed to do nothing but fill out some form)? I suppose getting a new job would be difficult because they wouldn’t have proof of the right to work in the UK, but an existing employer wouldn’t have to check again?
PS phoog's link seems to suggest that if the government found out today (14 months past the deadline) that you didn't apply for settled status with no good reason whatsoever, you might be in trouble. Or not. You would be asked to apply ASAP and give a good reason why you didn't apply earlier, which you couldn't.
There are certain rights that are "guaranteed" with settled status, for example benefits, but I don't know what happens if a right is "not guaranteed". And it seems nobody is looking for you.
There is also the strange fact that the government refuses to give you anything saying that you have settled status in writing. That means on the other hand they can't complain if you have no evidence in writing. The best that you can do is go to the website that is about "permission to work in the UK" once a year, and take a screen shot. So if they "lost" your settled status like in the Windrush scandal, you could prove that say 7 months earlier, and 1 year 7 months earlier, and 2 years 7 months earlier, you were told you had the right to work in the UK because of settled status.