I think Xavi's decision to resign is the right one. Xavi loves this club. And he is a living legend of Barcelona. He was the coach of this club for the last 2 years. And despite Barcelona not being in a good position, the team won the La Liga title last season with the help of Xavi. But now Barcelona face a bigger problem. The team's performance this season has been erratic. Also their financial condition is not good. So Barcelona needs a more experienced coach.
If Xavi remains as the coach of the team, it will not be good for Barcelona and Xavi. Barcelona fans might start trolling Xavi too. Perhaps this is why Xavi has decided not to stay at Barcelona at the end of this season.
The lack of strong support from management for Xavi in building the Barcelona team makes it difficult for Xavi and I think Xavi's decision is very correct, in fact if he continues to suffer a downturn with the Barcelona team it will make his coaching career even worse.
However, I am sure that after Xavi's departure it will not make the Barcelona team much better and in fact I am sure that Barcelona without Xavi will get worse.
Teams that do not have strong finances will find it quite difficult to compete with the top teams in La Liga or Europe.