I’m not sure it’s fair to say it’s all been disappointing since then.
Rain was the only thing stopping us winning the home Ashes - yes we made mistakes in the first two tests, but if the weather had held then no-one would remember that. We embarrassed the Aussies in the final three tests. Definitely disappointing not to get the win but we were quite clearly the better team and the ‘moral’ winners as Australia were only saved by rain.
India away was disappointing but they’re a great side at home with some of the world’s best players. New Zealand away was disappointing, agreed. Couldn’t have done much more than what we did against the WI and against Sri Lanka we only dropped off with the series won and Stokes absent.
As you say however, rightly or wrongly the whole thing will be judged on the next Ashes. Win that and Bazball will be seen to have been a resounding success. Even a draw would arguably put a positive shine on the era, especially if we also beat India and Pakistan. Lose however and it will just be seen as a fun but flawed way to play cricket…
Moral victories are for losers!
We utterly battered the Aussies in that home series all summer, but still lost the Ashes because of a series of dumb tactical decisions in the first two Tests. Just as we didn't win the series in New Zealand because we made an insane declaration because "we don't do draws". Both of those are squarely on Baz and Stokes' heads.
And we could have done better this summer - we could and should have won every Test (given that the weather didn't ruin any of them).
The 2004 team won every Test that summer - seven games against much better opposition (a West Indies team that actually had some players that had played in England before and New Zealand). They were a great team. This England team still hasn't convinced me that it's anything more than loud. And it won't unless it a) beats India next summer and then b) as you say, at least draws the series in Australia.