Land is sort of a good example (there is scarcity involved, which makes it not a perfect analogy).
Land doesn't have any intrinsic value. There are two reasons (unused) land has value:
1) Someone expects to be able to use it to create value
2) Someone expects that someone else will want to use it to create value in the future and they expect that scarcity will come into play allowing them to charge more for it in the future than it currently costs to buy.
Land is only staggeringly expensive if either the value expected to be generated from 1) is exceptionally high or the expected value someone else will generate from it in 2) is exceptionally high.
If those aren't in play, you can get land very cheaply, or even for free, or in extreme cases be paid to take over land (that usually only applies for contaminated land etc).
To a first approximation, the good ideas are precisely those which can be used to create a lot of value: they're the land in Shanghai. It's not clear to me in what sense of 'intrinsic value' such land or ideas would lack it while (say) a pile of high-quality bricks would not. Conversely, if ideas are worthless only in the sense that building materials or pig-iron are worthless then in any ordinary sense they are not worthless at all.
Obviously ideas are less reliably scarce than land, because a number of people can have the same idea independently, and also because once another person hears your idea they can steal your fire without paying you, so it's difficult to trade an idea in a way that doesn't remove your ability to capture the value from it. But a high-quality and unobvious idea tends to occur to only a few people at any time, and the awkwardness of trying to do deals with them is far from rendering them valueless either. It's certainly not the case that good ideas are plentiful in the sense that if there one specific good idea to solve your problem but you don't think of or hear of it, then don't worry, there are lots of similarly good and suitable ideas lying around and one is almost certain to come to your attention soon.
A different, and notable distinction between land and ideas is that people are usually better at recognising valuable land than good ideas, as Frank Aiken observed https://en.wikiquote.org/wiki/Howard_H._Aiken . This is one reason why some ability to "finish" (in terms of external circumstances as well as internal factors like temperament and character) is such a valuable accompaniment to having a good idea: it helps to have something relatively tangible (be it only a prototype) to force down others' throats.
Land doesn't have any intrinsic value. There are two reasons (unused) land has value:
1) Someone expects to be able to use it to create value 2) Someone expects that someone else will want to use it to create value in the future and they expect that scarcity will come into play allowing them to charge more for it in the future than it currently costs to buy.
Land is only staggeringly expensive if either the value expected to be generated from 1) is exceptionally high or the expected value someone else will generate from it in 2) is exceptionally high.
If those aren't in play, you can get land very cheaply, or even for free, or in extreme cases be paid to take over land (that usually only applies for contaminated land etc).