Though I am not sure about the actual historical details around the process. One of the advantages of Tintype is that you can process them right away, which was suitable for portraiture. Didn't a lot of photographers go a town to town to do this as a business in US? I would think that this was a part of the reasons.

Also, it is a lot easier to do it in a studio setting since you do have to carry your entire darkroom.

I would also think historically there weren't "landscape" or "architectural" photographers who would limit the potential of mass-production of their images... Wet-plate negatives are far more convenient for them for their use.

These are reasons that I can think of right now.

There are people who shoot landscape with tintype now. They carry their darkrooms with them where they go.