It's far harder to move citizens between countries and would basically be impossible on a large scales like this. Currently people are free to travel between states but who knows in 5-10 years? They may make women take pregnancy tests at the borders of states.
Somewhat. They're free to travel, now, as you say, but Missouri now has the crime of "conspiracy to commit abortion" to cover you getting in your car to drive out of state, or booking a flight out of state...
It's just good business. There are lots of women at Google who are valued contributors and will leave if they are forced to live in a state hostile to them. Google can't afford for them to leave. Ergo, Google creates an environment where they can avoid hostile states and continue working for the corporation.
There's a famous virtue-signaller in my area who drives to work every day (construction) with trump flags on his truck, and he pickets an intersection near my house with a "trump won" sign most weekends.
The far-right has themselves a major virtue-signalling epidemic they aren't admitting.
Do you see companies investing their money to give workers a better salary or better working conditions? No. But they invest a lot of money in lobby to take away worker's rights.
Do you see companies moving their offices to places where people have better rights, which usually translates into better salaries, better benefits, better working conditions? No. But they spent lots of money moving their operations to places where people have less or no rights at all.