Edit: to be clear, I don't mean things like knowingly lying beforehand, but if circumstances drastically changed, I would 100% expect companies to rescind outstanding offers, so I similarly wouldn't hold it against a candidate for rescinding their acceptance if their circumstances changed significantly. It's reasonable to expect both companies and candidates to act in good faith, but it's unreasonable for them to face significant hardship just to honour an offer if their situation changes.
Replace companies with jobseekers.
Some jobseekers don't do this sort of thing. That others do doesn't justify making this sort of choice with every jobseeker.
I've talked to recruiters who have been rude to me for refusing to "give a number" as in my expected salary/wages. I also do not recommend accepting offers and then backing out. However, I submit that there is no company, even if you founded it yourself, that deserves your loyalty forever.