I had a pretty similar experience: spent a decade (2007-2017) working professionally in Haskell and just got completely fed up with the state of the language, ecosystem, and community. I migrated most of my new work to Ocaml and haven’t looked back.
For me I think the failure of the Haskell Prime effort to establish a successor standard to Haskell 98 was a big factor: the language and ecosystem became more chaotic and inconsistent over time as people drifted away from any hint of a common standard. Add to that the changes in the community when there were big changes in the cohort of “leaders” who had driven things from the 90s until the early 2010s (eg, when both Simons changed their roles). The folks who took their place haven’t done good things for the language in my opinion.
For the reference, 2017 was the year of GHC 8.0. Since your decision to never look back there were a lot of good things.
The standard didn't come out because of some failure to make it. It was mostly the lack of interest that killed it. I wouldn't be betting that some alternative universe where Haskell Prime pulled through had a noticeable increase of adoption because of this.
Looking at proposals, arguments "from standard" don't tend to generate enough support. What wins hearts is alleviating someone's pain without taking disproportionate externalities.
I’ve paid attention to the language since 2017 (it’s kind of impossible not to if you work in the PL research field). I just consider it dead for my own work - that’s the sense in which I haven’t looked back.
For me I think the failure of the Haskell Prime effort to establish a successor standard to Haskell 98 was a big factor: the language and ecosystem became more chaotic and inconsistent over time as people drifted away from any hint of a common standard. Add to that the changes in the community when there were big changes in the cohort of “leaders” who had driven things from the 90s until the early 2010s (eg, when both Simons changed their roles). The folks who took their place haven’t done good things for the language in my opinion.