LoL was free2play from the beginning.
At the start Riot had great intentions, and it seemed to be in a good place. The 40 champions were unique and fun, and it wasn't overly unbalanced.
It's learning curve is tiny.
There is no difficultly in selecting items, no STR/INT/AGIL. It's just stack HP and your AP/AD.
Because of these reasons, we all invited our friends, who invited more.
And it sort of carried on to a point where Riot only cares about making cash now from making OP new champions and silly skins.
LoL died *for me* when Urf died. All those years back. I still play it now and then, but it's a horrible community.