It is to disincentive those on a temporary visa to apply for permanent residency, without eliminating the visa path entirely. What your mental model is optimizing for (easy, efficient) is different than what they are optimizing for (hard, inefficient).

https://www.bloomberg.com/news/articles/2026-05-22/trump-to-...

> The policy change could impact hundreds of thousands of people a year and potentially reduce legal immigration further amid a sweeping government crackdown, according to immigration-law experts. President Donald Trump’s administration has introduced a series of restrictions affecting everyone from asylum seekers to students and highly skilled workers.

> The new rules generally apply to any foreigner who came to the US on a temporary non-immigrant visa, including students, employees on H-1B or L visas and visitors. The US awards about 1 million green cards a year, though roughly half of those are for foreign relatives being sponsored by an American citizen. Those applications are generally already processed outside of the US.

(POSIWID [The Purpose of a System Is What It Does])