Because becoming an architect takes years of education and training. You have to fight and juggle the demands of clients, planners, neighbours and the occupants. It's expensive. It's slow. Most architects don't get to build anything significant until their late 40s or 50s. You're very likely to lose your job every time there's a recession.

With software you can make whatever you want, right now.

Well you are an architect in a way, you may not be building things out of trees, but you should be building things out of thoughts.

Thoughts may not clean our air, but well directed thoughts may do things just as impressive :D