Again, you are presenting just 2 options like they were the only 2 options. Remain small or grow big.
They could have started small and expanded after release, pleasing both those who wanted smaller scope and earlier release and those who wanted bigger scope and are fine with a later release.
EDIT: Ill give what i think is a pertinent example.
The game is currently lacking in gameplay loops and careers. The crowning achivement of the game so far seems people standing on a station saluting each other (joke).
But they decided to make planetary landings a focus now. Why? Was it because ED released Horizons? CR just had to also get planetary landings in SC at this point? We know CIG decided to change planetary landings well before the plan for 3.0 was revealed.
So, they are now using planetary landings as one of the reasons for delays, because of the increased scope. Why not instead focus on space based gameplay for 3.0. Careeers and missions, get full gameplay loops in the game set in space, then expand and do planets. You can always have a small team on the side working on the planetary tech.
Then for 3.0 people would have had a much more playable "game".
Ok, maybe it sounds like im saying CIG should have done it that way because thats the way FD did it with ED. But to me, it does seem like the better way. Give players something to play and get it out there in a reasonable timeframe, and SC might by now have had mining, trading, piracy, etc, as well as more space based locations, even if only in a basic form.