I've been using a hobbyist version of Mathematica through 3, maybe 4 versions... cost me $99 USD initially, but everytime I've upgraded, it has cost me a little more. The tool is fabulous for math-intensive stuff (RF work, information theory, other cool stuff), but it's worked out well for Wolfram (the publisher), too -- they've made ~$500 USD off me over 5-6 years, just so I can "scratch a math itch" for tech weenie stuff I was interested in...
Bottom line is, these "hobbyist sales" are generating incremental revenue for products whose main focus is in technically-challenging and high-value (financially-deep) applications. Since the kicker for many of these "hobbyist-grade" products is 'no technical support', the marginal cost of selling these products at a large discount to hobbyists is near zero $... The margin is probably north of 90%, so any incremental revenue goes right to the bottom line! Plus, the vendor gets the 'goodwill and familiarity' bonus as well!
Vendors who miss this opportunity are really missing out on something.