At least mine is still running strong, there are contributors that are still subscribing to My Next Manager due to its reliability and resilience to outages…I guess some Nest users want to play with their Nest devices till the end of the program…
But, you’re right, it’s the end of the Works with Nest program, and Nest is a rabbit hole (or more a dead end)…
I’ve always been a strong advocate of the ecobee ecosystem (which is growing soon with the addition of the ecobee cam, and the smoke detector), and I’ve been right all along…
Good luck with Google assistant, you’ll need it (as the limited APIs will make the Nest HA very limited)…