[p_l]

The equivalent of greencard in most countries (permanent residency) usually requires that you're in the country, not outside, and the process is heavily reliant on you being present in country and able to show history of legal (temporary) residence.

[gventura18]

The majority of people granted greencards are family/relative sponsored who apply outside the US. Only in the past 15 years have employee sponsored greencards surged, most of whom have temporary visas.