That doesn't add up, in this case. If they simply announced a revenue share, something that Unreal Engine already has, it wouldn't have been anywhere as controversial. Some devs would grumble but it wouldn't have been taken as an existential threat worth jumping ship as soon as possible.

The whole charge per download was likely an attempt to get more money out of freemium mobile games, but nobody was willing to accept that.

Really, the damage to their image so significant, it's likely many dev studios will drop it even under those conditions, just out of lost trust.