Correct. However many companies will hire someone on a OPT and then apply for a H1B. If you don’t have OPT they probably won’t go through the hassle of sponsoring you for a visa if they want you in a US office.

3 years of OPT gives a companies lawyers plenty of chances to apply, get rejected and then reapply. This is the case with my company right now. I.e the first step in our hiring processes is asking if you are authorized to work in the USA? A no answer equals likely rejection.

OPT increases the probability that you will be able to get a h1b.

If you reduce the number of students you narrow the funnel.