I can't specifically answer, but I can give some extra information

Most plants are autotrophs, which means they can synthesize their own material from a set of basic elements and sunlight. This makes them a bit easier to grow in general.

Many fungi (and a few plants) are parasitic/symbiotic on the roots of other plants. Becuase of this, they are harder to culture. You can't just grow them in isolation, you need the organisms they depend on as well....or at minimum you need a replacement.

But with mushrooms it's even harder, because the mushroom is essentially the fruit of the fungus. And the fungus won't send up mushrooms unless environmental conditions are right. So not only do you have to grow the fungus, you also have to figure out how to get it to fruit.

And finally there's a question of demand. There has been progress made in culturing truffles, because truffles are super valuable. But most mushrooms don't have millions of dollars poured in to figuring out how to grow them, so nobody's figured it out yet.