I think it's a bit more insidious than a bi-annual talking point. Sir Paul McCartney, Sir Bob Geldof, Sir Mick Jagger, Sir Elton John, Sir Cliff Richard, Sir Lewis Hamilton, Dame Mary Berry, Dame Twiggy... their Sirhoods or Damehoods are routinely trotted obsequiously out by the media whenever they are topical for some reason or other, reminding us of...what, exactly? The fact that they were in the right place at the right time to make themselves as rich as Croesus? The fact that the establishment has embraced them cordially and that, having had their profiles raised in consequence, they've gratefully reciprocated? Despite the fact that some of the above may have made philanthropic donations that I haven't heard about (accompanied usually by little actual effort on their part, Sir Bob temporarily an honourable exception), they have taken a good deal out without putting much back apart from entertaining us (earning even more money in the process, of course).

Knighthoods (NOT 'sirhoods') just for making money?
I thinks Bob Geldof received his honorary knighthood for making money for charity (Live Aid/ Band Aid). Of course, being an honorary knighthood he is also not entitled to be 'Sir Bob'.
Sir Cliff's knighthood was also for services to entertainment, and charity work.