New around here and back in C4D land after a VERY long break. I was an avid Modo user and also I'm a former Foundry employee from back around the time of the acquisition 😅 although I was a designer, not a product manager but I do still have a bunch of friends there and sadly when development stopped, some of my friends got laid off.
The TL;DR of why modo probably isn't around is its small foothold in professional markets. It's the best modeller out there, nothing else even comes close. There's one or two people in most VFX studios and they're generally very happy and very productive. But Modo in its early days had a huge number of hobbyist users. Post buyout, they started leaving in droves, in part initially due to the Foundry wanting to push it further into VFX (Which didn't work) and then they pivoted to a number of product design contracts and focused a lot of development there. The hobbyists initially frustrated and then priced out, they left mostly for blender.
A lot of professional users stuck around, but those relationships often became more strained over time. Modo was never the most stable application and it's had a rocky history with stability depending on release. Some might bring some awesome features, but it also might crash 10 times a day. A lot of them left too.
In terms of features though, there's a lot of incorrect info out there about Modo - it had a rep for only being a modeller, which just wasn't true, it had a bunch of awesome features: Dynamics, some pretty decent mograph/replication tools, sculpting and painting (About on par with boy paint FWIW), a kickass (But CPU only) renderer, super intuitive material workflow, some fairly decent animation tools and some crazy customisation capabilities.
But it was very much a jack of all trades and none of those aspects were strong enough compared to the modelling. It was either "it only does modelling right?" or "Every feature apart from modelling sucked" the truth as always was somewhere in the middle. It covered a lot of the same ground as Blender, with a lot of the same weaknesses - it just cost much more 😂 I imagine unless you were a serious modeller and super committed it became a very hard sell.
I've now made the decision to move the bulk of my work back to C4D, as I'm not a huge fan of Blender and hate Autodesk with a passion. I've always had a soft spot for C4D and it was my main package for about 5 years before Modo. I'm not a super serious modeller and most of what I do is product shots and mograph adjacent things.
I'll still be doing my modelling in Modo for the foreseeable though, they've issued a 10 year EOL license that anyone can get ahold of. My commercial license runs out next month.
...that was quite a long TLDR, but someone might find it interesting IDK.