> then the product stops being superior, but it still has everyone's contacts, so most users stay

You're just twisting words here. The fact that switching costs are too high means it's superior. You're defining superiority to be some very strict UX that you've decided.

> then the product keeps getting worse until it's unbearable and everyone switches to the most popular superior alternative

Exactly. Once it stops being superior than people switch.

Except that the superiority, at this point, has nothing to do with the product itself. It is primarily—possibly solely—due to who else uses it.

That is not something that WhatsApp chose, or designed, except in that they hoped that everyone would be using it.

This is not a free market, where the product in question is something that one simply purchases and continues to purchase, and can switch to any other product freely. The products in this space are, to some extent, non-interchangeable (Facebook, Twitter, and WhatsApp may all offer online communication with other users, but if the users you want to contact are only on one of them, that is the only one that is useful to you), and there is a significant barrier to exit.

So a product that no one would have willingly chosen to start using may still end up being used long after it is, objectively, inferior to every other offering in that product category—so long as the people using it still need to communicate with each other, and cannot easily coordinate a mass exodus to a different product.

> You're just twisting words here. The fact that switching costs are too high means it's superior.

I don't see how high switching costs implies superior, nor how that's part of a definition for superior. For superior app I'd consider that to mean if it's better. It's also weird your usage of superior has shifted. You've stated it became bigger because it was superior; meaning superior is not about how much used it is. But you also define superior as having pretty much everyone use it. This seems to conflict, no?

What? I never said they were mutually exclusive? Far from a conflict, what you're describing is exactly the network effect: it both became large because it was superior, and it's size/growth contributed to it's superiority. This is the flywheel that is the network effect.

If only that flywheel didn't throw off all common sense and "don't be evil" tendencies... greed dominates eventually and everyone pays the price until a critical tipping point event comes and everyone finally realizes they have to go now.

Those tipping points are just too subtle until after a lot of damage has been done.

You're talking about superiority of experience (product + network), other people are talking about superiority of product, and saying that the network effect should be counted separately

I think you're making a good point that doesn't deserve the downvotes. There is no need to see vendor lock-in and efforts by companies to create it as anything more sinister than the free market at work. The network effect is a double edged sword. The world switched from Myspace, and it happened pretty fast. Switching has only become easier and easier since then.