I hardly think Ayn Rand is "the truth." On the general philosophical musing level you're probably right though. Conservatives can do much better with a channel of non stop "liberals bad!" than a movie. Most liberals have a shorter attention span for political themes, thus the crap that is MSNBC.
It doesn't mean bemoaning the lack of conservative Hollywood stars is effective though. They've certainly been there, like the examples I listed plus people like Schwarzenegger. Conservatism is just darker and less pleasant these days. Under Reagan it was about inclusiveness and bringing hope to everyone, thus still allowing Hollywood success. Nowadays people are regularly drummed out of the Republican Party for lack of ideological purity, Communism style.
Before he shifted to making movies to take vacations I think Adam Sandler represented more of that past ideal.