I get this. For me it just takes going to the basement. There you will find a home office with four large bookcases and a huge U shaped desk for my wife and I. It is all very nice, designed in CAD to the last screw and built, sanded, stained and installed in a room I finished from wiring to paint. It is the nicest place in the house.
But today the thought of doing a 100th of that tires me out.
There are many more things I used to be able to dream into existence, but time changes priorities. I still dream of that workshop/lab. I dream of Cathedrals on Mars and solving problems in math and physics. But those dreams no longer get me excited, it is all vanity and a striving after the wind.
That isn't to say those things aren't good, but I have a family now, also my body and mind are starting to betray me. All the wonders of the universe are not going to be enough for me now.
I do think I will reclaim the fire eventually but it lies on the far side of integrating those dreams into a larger eternal purpose.