From a play by Timberlake Wertheimer: "I don't think of it as 'selling out'. I think of it as 'buying in'."
When you go after the big bucks in a reasonably blatent commercial project can be called selling out. Often this is also called television.
However some may look at it as preparing for the lean years.
If someone says you're selling out, they have never bought a car, paid real rent, bought a house, gotten sick, had kids, or taken a real trip. Actors do not have to 'starve' just because they're actors.
You only go around once. Live comfortably and be happy. Happiness is so cheap and misery costs so much.
Also, if you are told you're selling out, there is a jealousy factor at play too.
Finally, Meryl Streep is doing Mamma Mia, for Chrissakes.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher