You can always throw a bunch of "what ifs" and "depends" in just about any scenario to twist it around and make it say whatever you want. It does not change my point. It is "unlikely" to be dangerous or cause damage - especially since it has been working.
And yet there have been tons of low-end generic and Deer PSUs in ancient Dells, HPs, Compaqs and off-the-wall brand computers still chugging along in offices and elsewhere that are 10 year old systems, totally caked in dust and carpet fuzz, not missing a beat. Poor quality does NOT automatically imply it is dangerous, or cause harm or become a deathtrap. Poor quality typically just results in premature failure.
I won't commit to any timetable. But if it has been working fine, there is no reason to suggest it is going to fail tomorrow. But it could - but then so could the highest quality model from the most reliable brand. It just "depends".