and if they could have unmarried couples in same room then that 1 room would cost more than a single occupant pays and then they'd have incomings from the 2nd room.
In short, ASQ would get more money from unmarried couples being allowed go share a room.
My wife switched from a non-O dependent (extension of stay) to an extension of stay for work without leaving the country. She's a teacher and they have been given permission by the powers that be to switch in country.
Assuming your wife's employer effectively sponsor your visa, they would need to work very closely with your new employer to sort it all out. You would need go cancel your current extension of stay but don't do this until your new employer has all of the paperwork needed at their end.
I'm not aware of any other professions being given this 'permission' mind.