Nowhere has it been argued that things do not change. That is why some clubs would drop out when necessary and some would come in when feasible. It is a bit like that NFL model that you argue before, but do not appear to be familiar with.
Not sure about the "things change" point, but anyway if the game can get the best and biggest clubs working well in SL it doesn't need change - (your "not neccessary"). Try the NRL (closer to us than NFL) works great without "change". Is "change" good? As I say change Leeds for Hunslet and Wigan for Leigh just so a few people can have some personal joy and we lose many fans and interrupt valuable player development, and produce a lesser product for the TV (your "not feasible").
"Change" would be brilliant if Bradford had dropped as a big healthy club and been replaced by another big healthy club, but here's the problem - the former drops out and is badly further hit by it - crowds drop young players stripped away, and the clubs that may exchange with them (had there been straight P & R) would bring few fans and no effective player development system.
Changing clubs in SL is absolutely no good for the game if it is a manifestation of business failure at one end i.e the relegated clubs AND failure to grow an adequate business to compete leading to inevitable failure of the replacement club i.e the promoted club. Change is failure all round, and that is in no way healthy for the game.
Change may come about from major private funding, like Fartown Widnes or HKR who changed the composition of Superleague, but even then these clubs would be nothing without their rich backers, shorn of their rich backers Wakefield and Celtic Crusaders went into admin. Small clubs Workington, Oldham, Leigh,
Halifax didn't have the rich backers so collapse was the result.
We can fantasise all we want but the great divide of the SKY money going to the elite and nowt to the rest is something we need to try live with not fight against to the detriment of important clubs like Bradford and London. Some people may perversely and selfishly find it warming inside that Bradford have dropped from SL maybe for some time whilst Fartown sail on on 5,000 crowds there but for the grace of one man. I can only think that the call for change in the SL guard merely comes from fans of clubs who want their own club to be the change, good for them but not good for the game.