"Abortion" is generally a shorthand for social conservative issues, of which there are many. Usually pro-aborts are also pro-stem cell, pro-gay, etc. Abortion itself has a range of issues, from partial-birth, which Arnold opposes, to public funding, protesters' rights, women's right-to-know, parental notification, Choose Life license plates. It is disingenuous to say that social issues, or fiscal issues, or even wide-ranging, important things like "abortion" or "taxes" or "guns" are just one issue. They are major cornerstones of Republicanism, not peripheral Republican issues like ANWR, which is part of an overall energy policy, which in total doesn't begin to compare to the aforementioned trio.
If Simon couldn't win against Davis when Davis was very beatable, no other conservative stands a chance.
Again, I think you're being willfully disingenuous. You know as well as I that if Simon had run a half-way decent campaign he would currently be governor. He squandered a great opportunity, but he didn't lose because he was a conservative. In addition, the winner in this election doesn't even need 50%, or the 46% (ish) Gray Davis got in 2002. Thirty percent will win, probably less, maybe much less.