Our current GitHub bill is $90/month, this would add an additional $700/month. I don't see how this doesn't cause a mass outflux.
Curious: Can you expand a little bit on your usage? $700/month equates to 350,000 minutes. Are you just running a truck-load of different Actions, or are the Actions themselves long-lived (waiting on something to complete)?
How much do you pay for the servers that run actions? Is it much more than $610? Then it kinda makes sense.