Various members of the Tory old guard such as Norman Tebbit have been railing against the coalition recently.
They can rail all they like but the glory days of the 1980s that they hark back to were very different from the 2010 situation that Cameron faced.
Margaret Thatcher had decent working majorities in all three of her general election victories. Even then though she demonstrated the sort of pragmatism needed to win and retain power. The 1979 manifesto was not exactly explicit about what she would do when she became Prime Minister and some of the radical steps she intended to take. She didn't want to frighten the horses before she had proven that she could be trusted with No 10. She also accommodated many of the Tory "wets" in her cabinet for a long time because she knew she needed to carry that wing of the party with her. As with all large political parties, it was a coalition in all but name.
I am certain that had Margaret Thatcher been faced with the election result that David Cameron had 2 weeks ago she would have pretty much done the same. She was all about getting and retaining power and the best way to have done that after the recent election was to make a serious offer to the Lib Dems. People like Norman Tebbit would not have liked it but if it was the difference between government or opposition he would have swallowed it.
Trying to compare the 2010 situation with the 1980s is like trying to compare apples with oranges.