You mean that tiny little UK that produces only around 2,5% of the gross world product? ;) Being fifth on a sorted list that is pretty long doesn't say much all by itself. The overall distribution matters, too. Seen that way, a successful company that is operating world wide and highly profitable could give up 2 to 3% of its revenue and continue to thrive.
However, I don't see how companies alone have the power to openly strongarm governments. It would be a pretty foolish move. But withdrawing from a country's market to cut losses can be a correct move.
Facebook's UK revenue in just one year (around £1.2b) is 4-5x what it paid to buy Giphy ($300-400m). They could exit the UK market just to spite the UK, but it makes no business sense to do so.
However, I don't see how companies alone have the power to openly strongarm governments. It would be a pretty foolish move. But withdrawing from a country's market to cut losses can be a correct move.