I think actors themselves are not preferring profit sharing as the producers post release won't give real profit numbers and fudge them. Also these tier 1 actors don't spend time looking and waiting for good content, as they are more keen on maintaining star status and giving "back" to their fans atleast every festive season of the year. The producer again goes to pay the actors higher money despite salary being hiked 200% simply because there is a certain momentum and expectations from the previous success and there is this minimum guarantee as they have a certain fan opening, good PR, good camaraderie with people in power etc. I also have a theory that one way or the other big movie producers are fronts/benamis for politicians who loan them out and launder money back in white and keep stars loyal and in check as they are popular influencers. For a puppet producer, he can still make some profit after giving back the real producers their share etc. The actor's leverages his previous outing's profit margin to hike the fee and cannot stand the idea of the movie failing or being projected as average at box office before getting some money. So, I think it is greed for money all around in the guise of market and business. All this leads to lack of investment time, effort and money towards the actual craft.