Yes Xavi is out of his depth here and I am the first one who thinks he can't turn things around. However, things are not that simple. It's not like there are 10 fantastic managers waiting to take over Barca right now. The easiest thing to do is to fire Xavi and than what? Who would replace him now? I sincerely hope people are not serious about Marquez taking over because he would probably be another bad experiment. This club needs a top manager with clear vision for the next 2-3 seasons.
IMHO the right thing to do is to hire a new long term solution in summer and not now. We simply can't afford to make another mistake. Furthermore, we should start talks with potential new managers right now and than make the right long term decision in summer. Firing Xavi now would basically change nothing. We would be in a situation we were when we fired Valverde and that ended up horribly. Making harsh decisions without a clear plan is foolish and risky.
Xavi makes it until the end of the season unless we look like missing out on the CL qualification.
Logically if we go trophy-less without contention in any trophy and with a downgrade in our onfield performances then we need to look at a solution for next season. One who can convincingly make the most of the squad we have today.
BUT, there is one other piece of data. If you look at 3 of the last 12 CL winning managers, or even stretch that to the last 15 champions league winners, then you will see that 20-25% of the recent CL winning sides have made managerial changes during the season, which is quite a stunning statistic considering it is the premier club competition in Europe.
So in a sense, given our trajectory and comparing it to those Bayern and Chelsea(x2) teams, a change right now may actually increase our chances of winning said Cup crazily enough.
And we all know there is no chance of it happening under Xavi, especially given his record in Continental KO games both in Europe and Asia, and his record against German/English sides with us.