I agree $6k upfront for startups is a lot (especially if they're just riffing).

But the bigger issue is there's no clarity of what this will cost if the startup works out and grows. So you spend a bunch of dev time building something that uses TLdraw and then its completely unknown if you can keep using it in the future as the cost could be $1 or $1 billion.

Any startup would be crazy to depend on a service with unknown pricing.

Sure you can email them and get the pitch by a salesperson, and use a bunch of time to get some long legal agreement with pricing in it somewhere, but that's what you do for massive custom-built enterprise tools. Not for on SDK in your stack. I don't think the opaque pricing model is common or viable for this kind of SDK. Imagine if payments providers or authorization providers or hosting all just had blank pricing and a "talk to us" button.