Even without free unlimited storage, Google Photos is still one of the best online photo storage services around.
I wouldn't call them the best. Most convenient, perhaps. But, I could be wrong, yet they allegedly also parse all that data and use it to enhance ad algorithms or what have you.. Viewed through that aspect, it wasn't ever really a free service, it's just that now they decide the tipping point from which they need to also start collecting $$ from end users.
I'm not a facebook user but wonder when will they also start charging - if not already.