As I said comparing hybrids to all-tube or SS is not apples to apples.
As to the price increasing of Fisher, part collector feaver, part realization that Fisher units both tube and SS were quite innovative and very good to excellent while Mc really did not concentrate on other than the separates and the tuner/preamps. It only was in the receiver and integrated amp market to have exposure and an entry point. Where as Fisher used the receivers more as an equal to its tuner, amp and separates lineup.
I've do love the 1700 and 1900 but would go with a 4100 if I were to go with and want a Mc receiver but, would first go to the early high end Sonys that were as well built and sound better. I had the Fisher 600-T receiver but it needed caps so gave it little time in system to prevent damage. It was good but from experience even with the capping, I do not doubt it would come up to the 1500 or 1700 for the most part. I did part with it before having it done but kept the TFM tuner and TX300 amp that makes up the 600-T and maybe one day will have them go through as both need recapping and I'd have them totally recapped due to age and reputation of the German caps they used.
As for values of the Fisher; I think you have to look at the engineering and quality of construction. 1st rate. As good and in some cases I think better than Mc. The company especially when they introduced their SS units with varactor tuners and presets and things like shielding. Their short comings were German sourced caps, early adoption of wave soldering that left cold solder joints until they nailed it down and in some cases plug in transistors that sadly are higher maintenance as to needing cleaning. Also, their early units used germanium transistors that were more failure prone than the later silicon. Working units tend to be fewer per thousand than Mc. as to the SS but they came out earlier than the Mc units.
As Mc did not have all-tube receivers, the contest is between Sherwood, Fisher and Scott. Scott and Sherwood were smaller companies and tended to be more regional based though of course Fisher's primary market was NYC but just NYC was larger than the Boston and NE market population wise and Chicago and region. The west coast was pretty much H-K, a consideration the hipping costs increases and product pricing when crossing the rockies in either direction. Also, Fisher covered more price points than either Scott or Sherwood. Sherwood for instance had only 1 fm and one am-fm receiver. I do think in absolute terms the Sherwood actually is the best of the all-tube receivers including the 500c and 800 Fishers while as a New Englander I also prefer those beautiful rotary dial Scotts, especially when there is soft illumonation on them. Scotts are between under the radar and coming out of the closet while the Sherwoods are a bit more out of the closet but not by much; they are hard to accpt because of the faceplate, love it or hate it, not being tall like the others and their simplicity of design that makes some think they were Muntzed which is far from the truth as they were the results of a purely engineering company with little spent for marketing.
I find the Fisher receivers good value for the money even at today's going prices that is a mix of collector and user pricing, whether tube, hybrid or SS but not necessarily the best sounding in any one category.