Most people are not ardent monarchists, but they support the monarchy for two reasons: 1 - Because it has always been there. 2 - They don't like politicians.
And here are some other facts to what you wrote:
1 - According to several experts, there are more people who support the monarchy today with a very critical press than it was in 1952 with a very uncritical press.
2 - There have always been many republicans in the parliament, but as former political editor of Sky News, and current presenter of Sky News Tonight Adam Bolton said in 2012, they are more careful about expressing them self now than they were in 70, 80 and 90s.
3 - It's also an known fact that if the young Queen had made some big mistakes in the 50s and 60s, it would have been much easier to abolish the monarchy then, than it had been today.
4 - William has not put a premium on privacy for himself and his family. He and Kate are not full-time working royals, but they have traweled on several official tours, did many walkabouts, he has given interviews both before and after he married Kate etc, and we will see much more of this in the future.
The monarchy is a big part of Britain's identity and as YouGov said last year, its here to stay.
This will be my last post on the monarchy's future in this thread.