None of us can get into Smerconish's head. Personally I don't think it's an act. People do change their views over time. Rush and Sean may well have changed their views over the past couple of decades but for them it's too risky to change the format.
When I read the last sentence you wrote, I come away with the idea that maybe you suspect that down deep Rush and Sean have changed their views in the direction that maybe Smerconish has changed.
Let me offer this possibility: Rush and Sean started out a bit more centrist but quickly learned how to put on the "rigidly Right" ACT because it seemed to play well with the audience. Is is possible that if Rush and Sean have changed their views, their "internal Clock" or internal compass if you please, has indeed changed.... farther and farther and farther to the right.
Who is the REAL Rush? Who is the REAL Sean? Does it even matter?
Who is the real Smerconish? Does it even matter?
Which brings us to the question of the day as framed by so much of Talk Radio:
Who is the REAL Thomas Jefferson? Does it matter?
Who is the REAL James Monroe? Does it matter?
Who is the REAL Ben Franklin? Does it matter?
We will probably never know the answer to any of my questions by listening to the radio.