I'm not going to go into the arguments about it, I've given you the link so you can read them all yourself. Though I will quote two big things (edited for note: assertions, not arguments for them; arguments are at the link above) against collapse postulates in general, since you probably didn't read them and perhaps you have a response why it doesn't matter:

"If collapse actually worked the way its adherents say it does, it would be the only non-linear evolution in all of quantum mechanics, the only non-unitary evolution in all of quantum mechanics, the only non-differentiable (in fact, discontinuous) phenomenon in all of quantum mechanics, the only phenomenon in all of quantum mechanics that is non-local in the configuration space, the only phenomenon in all of physics that violates CPT symmetry, the only phenomenon in all of physics that violates Liouville's Theorem (has a many-to-one mapping from initial conditions to outcomes), the only phenomenon in all of physics that is acausal / non-deterministic / inherently random, and the only phenomenon in all of physics that is non-local in spacetime and propagates an influence faster than light."

Second, now paraphrasing, is that many-worlds, aka macroscopic decoherence (QM applied universally), is a strictly simpler theory and Occam's Razor alone rules out collapse as it's an added detail not needed.

Lastly, this is just my own opinion, but just because you learned from a set of standard textbooks or from a physics department at some place, doesn't necessarily mean you learned correctly. Truth isn't what the university teaches, even though there's a lot of overlapping. (I have learned there are apparently still some people teaching that we are evolved from chimps.)