I worked with one developer who became a master electrician. He was experienced and intelligent but obviously burnt out on software. And he sure seemed happier when I ran into him a couple years after making that career transition.
My uncle who had a nice very senior eng job ago dipped out and walked into a plumber shop saw the help wanted sign in the window and they hired him on the spot. He then did that for 25 years until he retired. He said it was nice that the jobs were short and the outcome was usually very predictable but gross on many occasions.
Wonder how hard it is to get started with glassblowing
If you aren't a homeowner the facilities are the hard part. Need a large space where you can have a glass furnace and concrete floors that won't get damaged by molten glass. Lampworking is easier to get started in, but still need a place to run a torch (ideally with a vent hood) and store oxygen/propane cylinders.
Definitely go to a glassblowing camp if you are interested. If you have prior experience trying to control a fluid medium, like pottery for example, then that may help. In order to set up your own shop you'll want to be somewhere with low fuel costs.
The late Ezra Zygmuntowicz was a glassblower by training and trade long before starting Engineyard.
As a hobbyist? Not hard at all! If you're in a medium/large city, there's almost certainly one or two glassblowing studios around that have classes. As a career? That's a whole lot harder.