Consumers don't care how about Google/Alphabet organizes itself. Google owns Nest; that fact can't be avoided. When you own a company that intentionally bricks their customers' $300 devices for no other reason that they don't want to support them anymore, you're going to have to deal with the negative perception that it creates.

In this case, being disconnected is a deliberate choice by Google. If that leads to problems, they're still responsible. You can't just take your hands off something and disclaim all responsibility for what happens afterwards.

It was a deliberate choice by the former Google board, who no longer runs Google and now runs Alphabet. The blame lies with Alphabet, not one of it's many subsidiaries.

I think the problem is that Alphabet is basically what we used to call Google, and what is now called Google is just one aspect of what we used to call Google. Referring to Alphabet as "Google" is outmoded but it's sort of like saying "Blackwater" instead of "Academi."

They all ultimately answer to Larry Page, presumably.

All of the CEOs? Sure. Sundar manages Google though.

I think this is a little more tricker. When customers make buying decisions, there is "Nest, owned by Alphabet and not likely to be shut because they are broke" benefit that they get. When they fail to meet those expectations, it should and will certainly reflect on the trust for Alphabet. Mainly because of your argument: Alphabet has little control over the companies and one should stop expecting good treatment and product lifecycle just because it is under Alphabet umbrella.

If this is so true, then why don't the complete the task and spin the company off and hold a controlling share?

That's exactly what they did.

They did. 100% share.