I just had a hilarious meeting with a vendor.
We (at my day job) use a JavaScript library for a small but useful feature in our application. We've used it for probably the app's entire 10 year lifespan and haven't given it a second thought. Recently, a security issue showed up on a routine scan, implicating the (obsolete) version we use. So we have to get the latest version, and company policy requires us to get a commercial license to protect our own IP.
So we got in touch with the vendor, which took some doing because this library has existed for such a long time and passed through so many owners.
First problem: the vendor's sales guy didn't have the first clue what our app does, even when explained three different ways. I feel like I spread a little knowledge into the world when I spelled "actuary" for him. I hope he reads at least the first paragraph of the Wikipedia article.
Second problem: after I guessed (inaccurately) how many actual customers use the app, he threw out a license fee of $12,000 per year. I had to choke back actual laughter. I said "well, that's not what we were expecting; are you sure that's the number you want me to take back to our head of engineering?"
In fact, our license costs would probably wind up around $2,000 per year. But given that an entire library of tools like Syncfusion offers would only cost $3,600 per year and would give us all kinds of bells and whistles, not to mention an actual support organization and frequent, predictable upgrades, even that seems high.
So, in conclusion, if you produce a tiny JavaScript library whose functionality can be found in a few dozen other libraries out there, you may want to reconsider requesting a license fee so high that the customer's only rational action would be to swap your library out for another one. If it takes one of our developers two entire days to put in a new library, it would still be cheaper than the requested license fee.
Remember: price is a function of supply and demand, not of wishful thinking.