I don't mean to discourage you, your work is amazing.
But I would argue that printing isn't slower. Not when you count for being able to multi-task. By this I mean I can setup a job to print a set of them (say 64 of them) while I sleep, or while I'm at my paying job. Yes, printing one might take longer than making one from foam, but once you setup the job, you can do something else (work, sleep, play, honey-do list, etc).
I've never molded stuff, but I have a friend that does. And again, he sets up a mold that does a set (6 or 12 etc) and then pours them and goes to work, sleep, etc.
Now, I don't know cost. The range there can be HUGE, especially if you try to have something printed commercially.
Keep up the great work and love the pictures. I find it inspiring.