I am honestly jealous of the people who say they valued their university experience. I really wish I could have enjoyed formal education that much.

My life was funded by the ability to walk into software development jobs. If I were born 5 years later, I would be a different (probably non-functioning) person.

I think the vast majority has technically learned maths and physics outside the college classroom. The teaching quality I'm getting at my university isn't the greatest (bar a few exceptions), and I find myself regularly going to Khan Academy or 3blue1brown to understand a concept better. This is learning outside the classroom!

In a lot of ways, I find universities to be assessment centres and certificate issuers. Not in all ways of course, certain aspects such as labs, coordination of group projects, someone to ask questions to get back to you instantly, are all things which cannot be replaced in any circumstance. But when it comes to the dry theoretical stuff, I'm not sure why I would go to a lecture if I know I can get a better quality of teaching somewhere else online.

Of course this is only true for a few subjects (maths and entry level physics/engineering). I unfortunately have to rely on the lectures provided for the more specialist modules I'm being assessed on (such as heat transfer and chemical engineering principles). This is mainly so that I can comply with the teacher's specific assessment criteria and the terminology/definitions/textbook/ordering they use. I may be able to find heat transfer explanations somewhere else online, and they probably would explain things better, but they wouldn't help much when it came time to use the terminology that the lecturer expects you to use during an assessment, or if you're expected to use the equation sheet that the teacher made for you and expects you to use.

One of the most valuable parts of a Engineering/Mathematics Degree (Both at the BS and the MS levels) is that of the upper division elective courses for specialization. At research universities, these classes often contain lots of information/techniques that can't be found in a textbook, let alone in a youtube video. At best, there might be a very cursory blog post, or a collection of research papers that you really aren't ready to explore on your own. Often, these classes result in final projects which can be expanded into research papers or portfolio projects with the professor teaching the class, both of which are valuable learning opportunities for the student and effective signaling mechanisms post-graduation.

These classes are where the real technical value of a college education is found.

In addition, there a quite a few classes which are offered if not required for such Engineering/Mathematics students which are pretty difficult to approach on your own and surmise in a short period of time. For examples, I point towards Analysis 1/2/Complex, PDEs, Dynamics, and Probabilistic Robotics.

I personally got a lot from my undergrad, I (and this may only apply to me) strictly would not have succeeded in learning all the topics I did if my only motivation was my personal learning in my free time, particularly in the short time horizon I did. The pressure cooker (cough engineering school) I went through was very formative, built a number of professional/personal connections, and taught me almost all the personal and professional skills I have.

This is just my 2 cents though.

In fact, I will go one further. Almost all self-taught physicists I have met are kooks - bonkers crazy conspiracy theorists.