I've gotten the same impression. So many Windows tools are given away for free, no hint of ever monetizing or anything, just a hobby / service by the developer,

I've gotten the same impression. So many Windows tools are given away for free, no hint of ever monetizing or anything, just a hobby / service by the developer, and yet no code is provided. I remember hearing an explanation from one such solo developer with a relatively recognizable brand that he doesn't want people to be able to easily replicate his tools with added malware / adware. But I feel like download sites have been doing that for years anyway. He has released at least one tiny but useful piece of code as public domain. Also he does have one product that charges for. I suppose one potential reason to keep code private is to maintain more control of the free tools for purposes of branding and bringing attention to the pay tool? That's just a thought.