when you sue for damages, you sue the party who damaged you. if I throw a rock through your lenovo, you don't sue lenovo.

Yep also you signed a hefty EULA with Lenovo allowing just this. Lenovo uses the google home software modified for its product. This is the same problem android phones have. Google moves on and OEMs don't bother to keep up. Or OEM's contract end and they don't want to pay to renew. These hit the market in 2018 so they were most likely licensed in 2017, so that 5 year just expired and now they can't use whatever google service anymore.

That doesn't make it morally right, but legally, this isn't a case that's going to work out. If cases like this did work, the tech industry would collapse because every ambulance chaser would sue over any tiny software change.