It had a pretty clear resolution to your question when Trask was locked up (as the newspaper showed in the movie). Without Trask, the sentinel project = fucked.
It carried on with him dead, didn't it? Why would prison be worse for the sentinel program?
Again, as for the jet, the original XJet was created with work from Hank, who was flying the plane in the movie. What they were flying in 1973 was not the X-Jet, but it was a private plane owned by Prof X and worked on by Hank. They didn't go into capabilities of speed, but I would hazard to guess it was faster than your average private jet. If you can suspend disbelief about there being mutants that can read minds, have claws, and shoot lazer beams from their eyes, why the hell are you so hung up on them using a super sonic private jet in the movie when they clearly showed it FFS? I think you are being obtuse on purpose and have an agenda at this point against the movie or just trolling. Everything you couldn't understand or you thought was stupid has been explained out perfectly clear thus far. Arguing over shit like how fast their jet may have been in 1973 to do everything in a couple of days is stupid.
As for Professor X and using mind crontrol, he does and doesn't. He doesn't so much as use forceful mind "control" as instead uses mind "persuasion" on others. It's his ethical difference. He pushes people in a direction they may be less likely to take without that push, but it's a direction they may have taken on their own with another form of harder persuasion. He only uses direct controls in fights or emergency situations. Which he does use if needed. Don't be fooled by his power. He can shut down anyone and make them into anything he wants them. He could make anyone on the planet think they are pink fluffy bunnies for the rest of their lives (assuming they have no telepathic protection) if he really wanted to. With cerebro, he could do it to every human on the planet all at once even. This is why Professor X leads the X-Men and is one of the most powerful mutants on the planet as he is the most powerful telepath on Earth in the Marvel Universe.
I'm really not trolling and I'm really not stupid. I saw it with a few friends, and all of us agreed that it made no sense that Mystique's actions stopped the calamity.
They showed a super sonic jet in the future, not in the past. In the past, it was a regular private jet. Yes, it matters, because the entire premise of the movie rests upon the idea that things are happening simultaneously. But that doesn't hold up when you look at how long it would take to get the task done. Nor would it hold up when you consider that the timeline would be altered even if Wolverine delivered his message and went back. Maybe they would fail without Wolverine's help, maybe they would not. But I find the idea of Kitty needing to keep her concentration for that long absurd.
But still the bigger problem for me is the whole idea of Mystique somehow saving the day by changing her mind about killing the president. That is a load of crap.
Yes, the sentinel program may fail. Maybe some part of Trasks work is discredited, but not all of it. Consider this:
Humans and mutants alike both think in terms of us vs them.
Nixon and his cabinet would be thinking like that, and would not be included to trust Xavier, especially if they know he is a mutant.
They would be looking for SOMETHING to protect them against the mutant threat, and would undoubtedly use Trasks work as a base. Maybe you would end up with something worse than Sentinels? Just because Trasks work is discredited, does not mean that the idea of using violence to control mutants would die. Nor does it mean that the XMen would be guaranteed to triumph.
Magneto's actions in proving how dangerous mutants were would make things far worse for them, no matter what Xavier would like to do, and no matter if Trask is discredited. I don't know how you can't see this, and why you keep ignoring my real world examples.
Think about the cold war. Let's imagine that Jimmy Carter was campaigning for peace with the USSR, and suddenly the USSR threatens the USA somehow. Maybe the Cuban Missile Crisis #2. Do you think it would change his mind about the Ruskies? Or his Cabinet?
The point is:
Anti mutant sentiment would be way stronger despite what mystique said
With hate that strong, and trask having done so much work already, someone would find a way to continue his work.