Yeah go back a decade and Swansea were winning the league cup playing stylish football with Michu running riot. Southampton of course were probably most similar to Brighton are now, finding excellent players like Mane for low fees and playing fearless football under a highly rated young coach.
I think problem for those two clubs is they had takeovers and so change of direction meant endless errors with transfers and managerial appointments and then for mid tier clubs it dosen't take that many seasons to get relegated.
With the current structure Brighton are very well set though. Do wonder what Bloom would sell them for, pretty sure he's a lifelong fan so it would be a huge amount. Todd Boehly's probably had a crack already I'm sure.