The issue isn't them charging, but *how* they're charging. And who.
The way they're charging isn't predictable, it's not aligned with their customer base's business, and the charges aren't proportional to their net income but instead it "taxes" their visibility. Freemium and subscription services both rely on try-before-you-buy as *marketing* so not every install actually brings revenue. and without that marketting they wouldn't get enough attention to survive, even before the UNITY charges.
All charging platform holders only changrs *how* the money gets to them because, even if MS and Sony agree (doubtful), the money will stil come out of the developers' payout, and will be capped at whatever the developer contracted.
Trying to drag in the platform holders is not going to work.
Whatever fee they end up with needs to be predictable upfront and based on *net* without killing the geese.
This has no good outcome for UNITY.
If they can't survive without the surcharges, they certainly won't survive without the developers, and a good portion of the developers won't survive with them. After all, the main reason they got those developers was by being affordable.
They clearly didn't think any of this through.