He is getting money, he started the business with a loan IIRC, he's located in the Czech Republic which means that the cost of some of those things isn't as high as you would expect.

He's selling them at around 150$ per tube, his complete Nixie tube clock sells for 1700-1800$ and he's shipping these units about as fast as he can make them.

The volumes aren't high but like with any other artisan crafted item they are making money of it.