ED is not the ideal space game.
It's not even the ideal realisation of the universe David Braben has been building for 30 years.
It's not the game that was envisioned by the backers during the Kickstarter, nor by the design team during the DDF.
What it is, is a really really good space game. The best realisation thus far of the universe David Braben has been building for 30 years. And the closest anyone has come to the game envisioned during KS and DDF.
And it's improving, albeit slowly, over time.
Will it ever be ideal? Doubtful, if for no other reason than there'll never be consensus on what "ideal" is. Will it ever fully realise David Braben's vision? Unlikely, for similar reasons. Will it one day match the specifics of the KS / DDF? Probably not, but its popularity may pave the way for the next, closer, iteration.
There are many things ED is, and many that it isn't. The one thing it's definitely not is a failure.
Addendum: On a specific note, because I see it's been mentioned a few times since I started drafting this: At no point from announcement through design to development of ED did I think for a moment that all 400 billion star systems would be "filled with content" whether it be FD-written or player-generated.
They're filled with procedurally generated worlds that look amazing, many of which I can land vehicles on. More ways to interact with those worlds come with each major update. More and different planetary types are likely to be added to the list before the game reaches end-of-life. Some of those worlds may be visited by hundreds of players, some by only me, some by nobody at all. Ever. To me, that emptiness is what makes exploring ED's galaxy special.
I honestly struggle to imagine it any other way, but then I have little interest in player-run economies or empire building. Mileages clearly vary.