With wenger you've gotta consider that if Ancelotti, Mancini and perhaps even Ferguson at this age went, well it will be 6 years now without a trophy, would they still be in the job? Very very unlikely
And you can talk as much as you want about good football, yesterday was not an example of good football, passing it in front of the box is not good football, there was zero penetration and no incision to your play. Man Utd were terrible in that first half as well, but they did display some good, effective counter attacking football in the second half, that was good football not the rubbish Arsenal played.
The only time Arsenal play their tipi tapi and find it effective is against rubbish teams, you will never touch Barcelona because your team does not have the steel nor the desire to close down on the opposition when they lose the ball in the manner that they do