To give a bit of historical perspective, the Macintosh IIfx was priced at $9,869 USD for 4 MB memory & 80 MB HDD in 1990. The NeXTcube was not out of line for the class of machine it was. Also, I remember someone telling me that Adobe did charge a fair bit for their Display Postscript.
I actually think one of the biggest problems was charging so damn much for the developer tools and their retail picks were less than helpful.
I got a copy of NeXTSTEP 3.3 and 4.0 with the developer tools and had a Microway server speced to run it (90MHz Pentium). It was way more fun and productive than any other machine and that includes the BeOS which was nice but felt a bit unfinished. The manuals were amazing and I wish Apple still knew how to do documentation as well as NeXT did.
It was also the case that Jobs was reluctant to sell them to the businesses that could afford them and easily justify the cost in enhanced productivity such as investment banks. He wanted to sell them to education at a time Sun was using some of their profits from banks to sell to education at a discount. A superbly effective strategy for Sun for many years.
Just the cost of that much RAM alone priced it out of the home market.
At introduction, a Xerox Alto would cost $100,000 to build in today's dollars according to Wikipedia, so prices were trending down at the time, but were still enormous.
Because they would have been operating at a loss. Unless they could magic down the cost of manufacturing their products, there's no way to magic down the price they had to charge customers.