I assumed GP meant that there's nothing in it for the user, only for the company.

Other examples include carrier-branded apps that come preinstalled on phones.

In this context, an earnest product could be a messaging product that aimed to solve a problem with other existing products and had a coherent story explaining this.

Allo from the outside seemed to solve no problem other than "people are using messaging platforms that aren't ours".

I think they mean it was a “me too” product. “Everybody’s using their messaging app. That should be us! Let’s make a new messaging app and take over that market.”

As opposed to a really new and innovative product (e.g. the iPhone) or at least one that’s a notable improvement over existing similar ones (Gmail).

It’s a spectrum rather than a hard and fast distinction, of course.

Google was clearly not strategically invested in Allo; as it was one of at least five messaging products? Duo, Allo, Hangouts, SMS app, the carrier RCS BS. As a consumer, when i see that, I know Google isn't going to continue doing all of those in two to three years, but I don't know which one they're going to keep, and it's not worth my social capital to get enough of my friends onboard to try it.

An earnest product is one that succeeds after a year or two, and the non-earnest are the ones that fail, duh!