I’d say Google Glass and Google Stadia are their 2 most well known failures. Or two of the more recent anyway.

But they made the failure that was Google Video, and then just bought YouTube because it was clearly superior to them.

They’ve tried to create a couple of social media sites, with little success.

Nexus Q never actually went to market.

Knol was an attempt to replace Wikipedia.

I think Google Fiber is still going but I feel like they underdelivered. More area should be covered by now. Some of that could be competition and legal battles, not on Google.

Mostly poorly executed, over-priced, or just generally unwanted ideas.

And as far as Elon delivered, you can add Star-Link and the flamethrowers.

I’d never even heard of Tesla phone, but after looking it up, I don’t think that will ever get widely adopted and is mostly a waste of time compared to EVs, internet, neural implants, and Mars.