If people are willing to spend the time researching, the money to buy, and the time to configure the hardware, I am a bit confused why spending a little time on the software is a hangup. I learned to use Linux originally when I was hacking on my TiVo's. I didn't learn enough to do more than copy other people's code and I lost interest. That was only because TiVo worked well enough as is and the few scripts I installed were basically copy/paste.
I do use Linux at work, but I don't do anything advanced in it. I have IT staff that cover any real issues, so I'm still just a novice Linux user. That said, with a little reading, a few dollars investment in a RPi, and some time tinkering I've been able to get a lot of different systems set up. I'm not saying it's as easy as Windows HA, but that's primarily because the Windows crowd seems more willing to part with the contents of their wallets than those that use Linux. There are a couple paid options on Linux (Homeseer being the main one) and they are great. If you want a more DIY approach, you have to DIY...
I wanted open source in case the project died (HG would be dead if it wasn't open source). I didn't realize how complicated HG was, so I'm not likely to code anything within the main system. However, it has various scripting languages that range from easy (Wizard scripts akin to AHP) to real programming languages (C#, Python, etc). Most of the flexibility in these systems is the fact that a REAL programming language is available. It is not a negative, it is EXACTLY why I picked HG in the first place. HASS, Domoticz, etc. also have these options, so they are on the same level.
I fully appreciate that it's intimidating to get started with Linux. Ironically, that is exactly why the RPi was developed. It was designed as a teaching tool to get students up to speed on Linux so they could have an affordable, fully capable computer that is capable of doing many things, programming included. There are easy installations available to get going if you want to learn Linux or other languages. However, if you just want a ready-to-run HA system, you will probably want to focus on one of the easier setups that either has an installation script or a RPi image. HG used to have an image. Domoticz has an installer (just flash Raspbian and run the installer). Homeseer has an image.