Don Pacifico this is such a binary summation of the situation though without any acknowledgement of the context (ie. We achieved our highest points total in an incredibly long time and got to a CL QF for the first time in a decade or so).
Again, I acknowledge that this season has been below expectation and progress means nothing if we don't win anything but I don't think we should be reframing last season as a failure. I see no reason why we can't rectify things next season.
I don't think that context is particularly of great significance if you are of a view this is where Arsenal should be at. I don't see many positive in the CL campaign other than we were finally back in the latter stages. We beat teams we should have and performed poorly when it came to the crunch.
Whilst we're on context, there's very little talk of it this season when the arguments are being made that we are still 2nd despite our issues - that is only because of an unprecedented and wholly unexpected collapse of the team which has dominated the league for almost a decade. But for that we'd be a distant third and considered well out of the running before recent weeks led a collective hammering of the final nail into this season's coffin.
I similarly can acknowledge last season was an outstanding effort despite the dreary CL exit and being pipped to the post by City in the league. But that doesn't mean it wasn't a failure. That we failed well doesn't mean we didn't fail.