The weird thing is, to me it seems that tools like PCB CAD is one of the few areas that I can see the hobby market being a non-negligible fraction of the market. There is no way that hobbyists are going to be more than 0% of the market for components, PCBs, and that sort of thing. One model of the iPod probably ships more silicon than the entire hobby market in a decade.
But the thing is, a garage engineer who turns out 2 prototype PCBs a year still needs a CAD program (also a multi-meter, a soldering iron, and so forth). I don't think the number of electronics hobbyists is a negligible. It isn't going to be huge, because those people can't afford the $$$ you charge large businesses, but it seems like it could be a non-negligible revenue stream.
I don't mean to imply there aren't downsides. Maybe your support costs go up if you offer a discount version to hobbyists, maybe you lose some of your pro customers to the light version, maybe a lot of hobbyists are going to pirate your software even if it costs $100, and who knows maybe you are worried that your product won't be taken seriously by professionals if you market a light version.
Those are all legitimate concerns, and would be fairly compelling if the company in question were the market leader and living rich. On the other hand, if you are a company struggling to find a niche with a shrinking market share and a faster shrinking market cap, dismissing potential customers as unworthy of even consideration is greek tragedy level hubris.