Unless they come up with a comparable "unlimited" plan, this year's (re-)launch of these by the major U.S. carriers is probably one of the final nails in the coffin.
Non-technical low-cost people probably aren't going to find Fi, and "power users" are going to go for unlimited, especially as data use climbs.
And... I doubt Google will keep Fi around to support a bunch of low-cost, "minimal" users. Where's the money ("new Google") and what's to learn ("old Google")?
Sigh. And just as the T-Mobile network (and Fi comes also with Sprint) was starting to look broad enough to warrant moving away from Verizon.
Well, as others have said, who believed it was going to last? For my own Google use -- which for me doesn't currently include advertising/marketing -- I've basically drawn the line at the "traditional" Google office apps. As far as I know, they still dogfood those, internally. Anything newer? Not worth any long-term investment / lock-in.
If I return to doing some web sites (a few people want me to, currently), I'll look into whatever are the current best practices for indexing high and being appropriately exposed on Maps and the like.
Oh, and, by the way, Site Search, just the other day? Really? You're already indexing it, Google? What does killing off this mildly customized search entry point save you?