Just a few years ago, im pretty sure you had to get married, they had to go out of country and file the residency paperwork, and then wait until they could be issued a permanent residency. If they stay married and lived in the country for at least 3 years (i think they could spend some time away) , they could file to become a citizen. The residency process took about 6 months.
Biden made it so if the spouse was already in the country, and overstayed thier original travelers / residency / student / whatever visa, or just entered the country illegally, they could apply for the permanent residency without having to leave.
The court reverted it back to the old rules.
I mean, this is just the requirement path for spousal citizenship. Other visas have different requirements. Here, You have an established couple. One person can definitely, legally, gain employment and save money for the process. Yes, it may cost upwards of $10,000 for just the residency. If ones already here illegally, and you've saved up that much, you could probably save a bit more and find a place to stay in another country. If this was during covid, I think the odds of a spousal immigrant staying in a camp on the boarder, are lower than for the people applying for asylum.
Honestly, anyone I've met, with a spouse from another country, has had no problem doing it this way. They meet while the one immigrating still has permanent residence in their home country. They commute and have a long distance relationship. They feel the risk of losing their family is too great, so they do it the right way. It's fair, to think that idea should extend to employers, as well.