Again, that's brand loyalty, not a brand moat.

Moats, as noted in Google's "We Have no Moat, and Neither Does OpenAI" memo that made the discussion of moats relevant in AI circles, has a specific economic definition.

The Seven Powers is considered an authoritarian source on business moats.

https://www.goodreads.com/book/show/32816087-7-powers

It has branding as one of the seven and uses coca cola as an example.

Switching costs only make sense to talk about for fully online businesses. The "switching cost" for McDonalds depends heavily on whether there's a Burger King nearby. If there isn't then your "switching cost" might now be a 30 minute drive, which is very much a moat.

That's not entirely true. They have a 'infinite' product moat - no one can reproduce a big mac. Essentially every AI model is now 'the same' (queue debate on this). The only way they can build a moat is by adding features beyond the model that lock people in.