"accomplished a degree in a host country and obtained a relevant job offer thereafter" is a very good proxy for a lot of desirable properties in immigrants, at least in Canada (per official statistics).
Besides, foreign education credentials and work experience can be very easy to fake depending on home country, so it's understandable that it's worth less in the eyes of immigration systems.
In Canada we have lots of foreign students, and while there are some issues (nothing is perfect), they pay much more than domestic students, essentially funding the higher education institutions. Education is some of the best things you can export, if done properly.
Thing is, if you want to hire foreign, experienced, high-skilled workers, by definition they won't hold a US degree.
The current system favors immigrants that can afford a Master's degree at low-tier for-profit universities (see what happened to the Silicon Valley University). The change will take this even further.
Canada has a non-trivial but straightforward path to permanent residency that tries to be fair to both domestic students and experienced immigrants. It's not really comparable.
Besides, foreign education credentials and work experience can be very easy to fake depending on home country, so it's understandable that it's worth less in the eyes of immigration systems.
In Canada we have lots of foreign students, and while there are some issues (nothing is perfect), they pay much more than domestic students, essentially funding the higher education institutions. Education is some of the best things you can export, if done properly.