This is so wrong it hurts me to read. Different mushrooms eat different things. Some eat dead wood. Some eat live wood. Some must have a symbiotic relationship with a specific species of tree. Etc.
Most Morels need symbiotic relationships with specific trees, and it takes a certain age of the tree plus years of growth for the fungus to grow large enough to start producing fruits (mushrooms)...
Needless to say unless you own land that already has these exact trees with the exact age required, and you innoculate the roots and wait years for them to colonize... it aint gonna happen. That's why people still go out and forage them. Same for truffles and many others.
The commonly grown ones eat very easy to obtain stuff like dead wood or grain.