People will be able to build their own minis, tiles and props very soon.
Building homebrew maps in foundry might be fast, it still looks like crap. We're in 2021.
The problem Talespire faces is that it does so much less than Foundry. It's like comparing MS Paint to Photoshop. A visually gorgeous MS Paint, don't get me wrong, but one with only a bare minimum of tooling.
I also get the impression that Talespire's future scope is mostly limited to visualisation. It's not aiming to provide character sheets for a hundred different systems, or automate hit and damage rolls, or provide shop and inventory interfaces, or visual-novel style character popups, or drag-and-drop NPC design, or any of the other thousand things you can get a Foundry module for.
Your attitude towards your competitors is pretty gauche. You dismiss features and the pricing model they have, etc., while they have been incredibly successful.
I'm always looking for interesting advancements in VTT, particularly because I've got a box with a 55" TV mounted in it I can put on top of my table for using them even when playing with friends in person, but as a potential customer, the dismissive attitude you've displayed towards your competitors has turned me off pretty significantly.