Of course there are games that already have proven this, most notably League of Legends (which is also mentioned in the article).
https://variety.com/2018/gaming/news/candy-crush-saga-1-bill...
See Jarwain's comment in a sister thread.
Riot is notorious for releasing new heroes that are behind a paywall and that are overpowered.
As for runes, IIRC you couldn't buy them with the paid currency, Only with the currency earned from playing. It's a moot point since they merged runes and masteries anyways.
You don't have the same pool of characters as other players who've chosen to pay for their favorite champions and this is clearly a disadvantage.
This is different from games like, say, Overwatch, where the entire hero pool is available to everyone (different game, sure but the point stands).