> I searched to see what an X1000 would cost, and the price was quite high.
> Beyond that, I don't think it was available for order.

Yes, the X1000 sold out over a year ago. Its successor, the AmigaOne X5000, has become available just now.

> why this third party Amiga hardware is so expensive?

https://en.wikipedia.org/wiki/Economies_of_scale
Btw, what does "third party" actually mean in Amiga context? :-)

> does Grunch automatically update its repository database?

No.