That’s definitely not true. I had PS+ back in 2014/2015 and all the monthly games I’d added to my library were locked when I canceled it. Per Playstation:
Once your PlayStation Plus subscription ends, content you previously downloaded at no cost as part of the subscription (such as monthly games) will no longer be available.
I regained access to them once I renewed my subscription later, but that’s not the same thing as “games you get access to forever, even if you stop paying.”
That’s definitely not true. I had PS+ back in 2014/2015 and all the monthly games I’d added to my library were locked when I canceled it. Per Playstation:
I regained access to them once I renewed my subscription later, but that’s not the same thing as “games you get access to forever, even if you stop paying.”