I think he wants people to hurry and buy it now before it goes up, rather than holding off and wait until it gets cheap enough.
That's a classical business move, like any "time limited sale", force people to buy it right now before they have the time to think whether they need it or not.
Yep. This isn't a store, it's an event. The price model is about introducing time pressure to motivate you to buy right now rather than take the time to investigate alternatives. If the price reduced as more were sold, it would motivate a competition around "how long can I risk waiting for the price to go down?" which would lead to people leaving and forgetting to come back.
Sure. Maybe not for a company, but a lot of times, people put logos on individual projects. Maybe not around the current price of $500, but at the earlier lower prices, I could see someone looking at a logo and impulse buying it for a public-facing side project they've been working on.
Yes, actually, there are at least a couple (one especially) there I would not think twice buying if I had any financial justification (a business to attach it to or even just expendable money). He gets this particular design style perfectly, and these are really high quality logos.
That's a classical business move, like any "time limited sale", force people to buy it right now before they have the time to think whether they need it or not.