Commodore's experiences were driven by the interactions between Commodore management and its dealer network, and should not be taken as indicative of some broader tendencies within the early personal computer industry. To support this assertion, I would point to the other early personal computer companies whose experiences were different from Commodore.
The first example I offer is Tandy Radio Shack. Tandy was early to market with moderately priced personal computers (original TRS-80 line), high-end business computers (Model II, Model 12, Model 16), and low-cost home computers (Color Computer 1/2/3). All three lines experienced marketplace successes and were sustained for years through retail sales at Radio Shack, despite the vast pricing differences. The systems available represented a mix of 3-digit and 4-digit pricing, and they were sold to all categories of home, hobbyist, professional, and business users. Tandy's approach was to own and control their dealer network, and this certainly gave them a different experience than Commodore.
Another example is the launch of the original IBM PC in 1981. This was an expensive professional, business system when introduced. Quoting from the IBM Archives: "Needing new channels to distribute these new computers, IBM turned to ComputerLand; Sears, Roebuck and Co.; and IBM Product Centers to make the IBM PC available to the broadest set of customers." It was not uncommon for Sears to carry big ticket items in their stores and catalog, and IBM's approach was to leverage its own dealers, plus dedicated computer dealers, plus department stores for their expensive new computer. When IBM followed up the successful PC with the PCjr, they also attempted to retail it through multiple channels. It did not find success in any channel because it was widely regarded by consumers as a poor product.
Another example is the Apple 8-bit line. The early model Apple II/Plus/IIe were in the 4-digit price range and sold through a network of computer dealers with great success. As prices of computers came down, and as new low-cost models like the IIc were introduced, 3-digit prices were common and so was mass market selling. Apple continued to sell Apple II through dealers despite the falling price, and also alongside more expensive products like the original Macintosh. Apple is probably the best example of an early computer company using multiple types of retail channels and selling computers on both sides of the "$1,000 barrier" with good success.
Based on these examples, Commodore's problems with securing a reliable dealer network for the Amiga were most likely self-inflicted, based on past policies that had a negative impact on Commodore dealers. During the aggressive pricing wars that saw the Commodore 64 fall from $599 to $199, some dealers were left holding inventory that they could no longer sell without taking a loss. Commodore alienated their dealers with their aggressive and rapid price reductions and with no offers to compensate them for the losses. As such, the dealers that survived developed a healthy skepticism of Commodore that would make them less likely to join forces with them for the Amiga.