With the recent fix of BasicMed pilots being able to act as safety pilots normally, there is almost no reason why any pilot with a 3rd class medical should continue to keep getting a 3rd class, and should instead switch to BasicMed.
And for those pilots who are apparently having difficulty getting their PCP to sign the BM form, I suggest going to AOPA’s website where they have an excellent write-up of how BasicMed works, and a short printout that can be given to their doctor. It seems the key point to make is that it’s like any other medical waiver that doctors regularly sign, and leave any discussion about the FAA out of it.