Steve Lukather did the solo on Physical in 1981, which was no. 1 for 10 weeks, the biggest hit of the 80's. He said he just got paid his straight session fee, and that's it.
Of course, he take it today. He said these days, even the best session men are lucky to get two or three bookings per year.
Had a buddy did an invention, company gave him a $10,000 bonus then they sold the patent for 200 million dollars. The problem is they forgot to get his signature on a couple of the patent documents, when they came back to him he charged them $500,000 dollars for that signature.