Post winning the league, Leicester were held up as the blueprint for teams outside the big 6, before that you had examples like Swansea and Southampton, all will be in the Championship next season.
Brighton and Brentford are the current examples, and their recruitment has been very good to be fair to them but I don't expect it to last for very long, and some of their fans I have seen seem to understand that too. The issue is clubs in these positions never last there that long because there's only a finite amount of times you can replace your best players that get poached with cheaper alternatives and it pay off, if you do have a longer period where it works, the recruitment staff usually get poached.
There's not really a secret formula to having sustained periods of time in the Premier League (with successful seasons thrown in,) it just needs deep pockets and the hope that you don't make too many big mistakes in a short period of time, as anyone from 8th down can go down in any given season.
