This is wrong, and I'm surprised it's repeated so often. Some ideas are better than others. If you doubt this, ask yourself if, when starting a company, you would choose a random idea or your best idea.
Of course you would choose your best idea, which implies ideas have different value.
EDIT: I'm happy to debate this point with anyone who would otherwise downvote me. Critical replies welcome.
ie: There were multiple ways that Google could have executed their goal of building a search engine (engineering, sales, etc). Even if you come up with a 'better' idea, it may not be successful/valuable if you execute it poorly and make the wrong decisions.
What you're effectively saying is that ideas have no value without good execution, which is of course true, but this is very different than saying they have no value, because after all, execution has no value without a good idea.
The difference isn't in the idea but the execution - hence the value.
EDIT: Oh I see what you mean now. By "you", you actually mean me. No, I couldn't, because Google has parlayed their initial good idea into a monopoly based on network effects, specifically the accrual of proprietary data (clicks) which I have no access to.
The idea was valuable in 1997. It's no longer.
i.e. "when executing"
But yes, other things being equal, the execution of a good idea is more valuable than the execution of a bad idea.
So if you want to keep any useful definition of "valuable", you have to concede that ideas can be valuable.