Mariam London is not a club that wants to break into their bank to buy great players, they only want players whose salaries are standard, Mariam London doesn't really want titles, they only want profits from selling their players, so it can be confirmed that it is very difficult for them to get league title, because they never want to keep their star players. They have released many star players to other clubs, such as abumayeng, vampersie, Mesut Ozil.
Arsenal want to win titles but they always fail in the end where their quality and effort is not what they want. They don't target top players and prefer talented players to orbit each season, which may be good for business but obviously it will cost him a lot of competition.There is no way Arsenal are not targeting the title every season although some opinions can be justified especially about the transfer strategy of players and the way they are active in the market.
As for Mbappe's transfer to Barcelona, I would use an analogy with the failed contract extension with Messi. The signing of Mbappe's contract with Barcelona is possible, but for this Barcelona will have to make too huge financial sacrifices, so most likely this transition will not take place.