So I decided to check some prices in 1992 computer catalogs and I'm not sure this is really true. Looking at the Tandy catalog[0], you could get a Tandy 1000 RLX with a 10 MHz 286, 512k of RAM, VGA and a monitor for $1K, but it didn't come with a hard drive at that price. The same catalog also lists a Tandy 1000 RL with a 9.5 MHz 8086, 512k of RAM and CGA/Tandy graphics for $500 without monitor. I think the 600 actually fairs pretty well against that machine.
Looking at a Sears catalog from 1992, they have a Packard Bell 386SX with 1MB of RAM and a 40MB HD for $1100, but without a monitor. The cheapest monitor option on that page was another $290.
Obviously two random catalogs doesn't give you comprehensive pricing data, but at least from this quick look it does seem like the 600 was reasonably competitive at the $500 price point it was sold at.
Seems to me the bigger problems were higher up the product line. Not having a real response to the rise of VGA (first introduced 1987) until October 1992 was a huge miss.
[0] https://www.radioshackcatalogs.com/flipbook/c1992_rsc-23.htm...
[1] https://christmas.musetechnical.com/ShowCatalogPage/1992-Sea...