Honestly, if you are a producer, would you rather work with someone, who always come well-prepared, studied the character ahead of time and always give it 120%. Or would you want to work with someone who just come to the set & wait for instruction?
Your reputation preceed you. Popularity comes and goes. But work ethic last forever. There is a reason why some actor/actress are being booked 6+ months ahead of time. And there are some of them, who just get the roles when the producer cannot find anybody else better. But some of them probably don't care anyway because they only want popularity as road to make money from events & commercial. An hour of event pay much more than weeks of filming.
For the record, Broadcast produces 3 lakorn at a time. For high profile lakorn, they will specify who they want and book their leads, months if not years ahead of time (Like Anne in Qi Pao and Choom in Dok Som See Tong2 & Buppa Suniwat). The lower profile ones, they will take any leads, assigned by ch3.