The whole HA landscape is changing, and I wouldn't disagree with some of your points. My timeline with Indigo goes back to 2014, not at the dawn of HA, but closer to the beginning. Back then, Indigo seemed very easy to use for novices like me, and as I kept adding devices, I was also adding knowledge of how to do things. I agree with you about the UI to some extent, and have resorted to using Python for a host of things I wish could be done in the UI, but can't.
I also wish the UI would allow things to be grouped together, so when working on a particular issue, so I don't have to jump between Devices, Triggers, Actions Groups, Schedules, and Pages. I'd like to see something more akin to iTunes where you have an Album of Devices, an Album of Triggers, etc, and the songs on those albums can exist in multiple playlists simultaneously. So when I'm troubleshooting an issue, everything is together in one place.
But I digress.
Most of the HA solutions I see all use the internet for a lot of their functionally. Personally, the reason I like Indigo so much is that almost none of it depends on the internet to function. I'm not a big fan of people making money off of MY data, so the less the internet knows when I'm at home, what I'm watching, listening to, or reading, the better.
Just like smaller retail faces enormous challenges from the likes of Walmart and Target, Indigo faces challenges from Alexa and Siri. The trick for Indigo will be to navigate, by all accounts, what will be treacherous waters ahead. On the other hand, Indigo has been at this much longer than most, and has an extremely solid "core" as you mentioned. At its core, it IS a solid product, fairly easy to understand and program for even the novice of novices, especially me. I just don't see a compelling reason to walk away to something with perhaps a slicker, shinier, voice controlled interface, that can't even do half of the things Indigo can do, all the while selling my data to the highest bidder. I like the idea that everything I need to interface with is in a single program, so I'm not jumping between different command and control programs to run my house, especially if the can't talk with each other.
And the support here at Indigo is unparalleled. Both Matt and Jay, as well as the whole community have offered tips, advice and help more times than I could possibly count. When Alexa doesn't understand what you want her to do, good luck finding someone to help figure it out.
Do I wish development would speed up? More devices added more quickly? More function added in? Of course, but most computer users of any program have a long list of improvements they'd like to see, so Indigo is hardly alone here. And as HA protocols begin to coalesce into something resembling a standard, I'm guessing those standards will be easily adoptable in Indigo, which only means a bright future ahead.
So for me, as long as Indigo continues to support me, I will continue to whole heartedly support the team and community here at Indigo!