The stretch goals are a bit misleading IMO. Theres 2 aspects of them: adding more content, and taking more time to add them.
None of the content is being added because a stretch goal came along, they've stopped them now and they could easily have stopped them at 23m if they wanted to. We've had a variety of stretch goals, we've had speculative stuff like funding a team to assess procedural generation technology (we have dynamic damage and ProcGen planets & landings from that), theres been new content like systems and ships, as well as things like picking the perk for the stretch goal like space plants and ship guns. The latter 2 of those was little more than voting which were part of the next concept round. The stretch goal didnt create more work, it was just how they were announced. They could have asked us once a month to vote, the extra $1m didnt dictate it must be created, the developers decided they had X ships the universe required, so pick half for this next wave, and the rest were coming in the next wave.
The ProcGen stuff involved hiring people to work on that, so it wasnt pulling people away from existing work (if it did, they were replaced) so it just created a new job and hiring needs. Its also gone on to save a drastic amount of time through removing levels of damage state, we just have a ship, a damage layer, and in some cases (as seen with the Starfarer) specific break points between structures on larger ships, but its also reduced the filesize of a small ship from 100mb to 10mb, which has huge implications for memory access.
Im not even too convinced any of the stretch goals involved taking more time either. It'll have involved paying someone to build the content, but we're over 3yrs in and we're hardly sat waiting for content. We'd welcome more, but funnily enough its content we've had from stretch goals. What we dont have is the tech in place to move players between multiplayer instances, to land on a planet, so if we've got 20 new planets and 50 more ships, the game isnt built and anyone responsible for the essential bits that are missing arent being slowed down because CR wanted a mining ship in the game or an alien system adding. Content isnt slowing down progress, and you could argue the ProcGen team have made producing that content even easier, faster, and less resource intensive. The core game is what we need, just as much as content, except people blame adding content like its slowing down the core game.
If anything is to blame, its money. More money has meant that they've been able to build the game CR wanted to. He didnt want to build the game to its original specs, thats basically all they expected they'd be able to achieve, it was an attempt to raise 23m, partly from crowdfunding with private investment adding the rest once proof was there to show support. At the same time, its that money which has turned the game from being a niche space-enthusiast title into a title that is far far broader and its not because its been dumbed down but because of what is possible.
Money has made it a better game, but its requiring more work.
I suspect if in 2014-15 we'd got the original Star Citizen as outlined, and we could also see the SC which is on its current path, and given a choice of only one or the other, most would want whats coming, even if its taking longer. I dont see how a space enthusiast could be disappointed in getting a superior title well worth the wait.
I actually miss the stretch goals, or more specifically, the little bit of information you'd get about something you previously didnt know anything about. We get that these days via other methods, like AtV or 10FTC, but it was something to look forward to when you saw we'd just passed another 1m milestone.