My guess would be that if Facebook and Twitter pulled out of the EU market instead of complying privacy rules then some other organisation would step up to fill

My guess would be that if Facebook and Twitter pulled out of the EU market instead of complying privacy rules then some other organisation would step up to fill that void. It wouldn't even have to be an EU company just one that followed the rules willingly. I'd better that even worse than the loss of business neither Twitter or Facebook/Meta would like to see a competitor have access to a protected market of the size of the EU.