I looked it up, and we were required to complete form I-864 "Affidavit of Support Under Section 213A of the INA". My wife, her grandmother, and her grandfather all needed to complete one, and when considered together, prove that they earned 125% of the HHS poverty guidelines. As my wife didn't have provable income (we were moving together), we needed to dig into their social security income and complete the forms. I remember feeling sad that I needed to ask for such personal information from them.

My salary in the UK was many multiples of this guideline, but _earning potential_ is not considered. Pragmatism is not really a service offered by USCIS, it's too political. To be on-topic: this move will disincentivize smart but not-yet-wealthy people from immigrating to the "land of opportunity". It was already harder than it had to be.

It has always existed, but how strictly it’s interpreted (i.e., just cash welfare, or also Medicaid, SNAP, and other means-tested benefits) has shifted between administrations. If you applied during Biden’s administration, I could believe the public charge rule was applied very laxly, particularly because it’s rare to get direct cash welfare in the US these days, and even less for an extended period.

How recently? As of about 2010, it was very much still there. I understand that is 16 years ago.