I'm not sure the high end will get higher (unless you count weird collectibles from Leica and friends). Phase One may continue to push further and further into the stratosphere, but that's a negligible number of units per year. The mainstream manufacturers have actually abandoned their highest price point (the $8000 high-resolution FF bodies are gone).
The R&D that used to go into $500 cameras seems to be going into $1000-$3500 cameras now. Canon, Nikon and Sony continue to make $500 cameras, and to sell a lot of them, but they are getting mailed-in updates that don't add anything. Meanwhile everything from $1000 on up to $3500 is getting a lot of attention, and we're seeing real updates and new models ranging from the X-T3 to the Z7.
I strongly suspect we're going to see three new APS-C action-oriented cameras in the $1000-$2000 range in the next year or so (Canon, Nikon and Sony - very likely all mirrorless). I'm also expecting two new lower-end FF mirrorless models from Canon and Nikon - in the same price range as the action-oriented cameras, but FF and lower speed. We may well see an updated Sony high-resolution body and/or a brand-new Canon high-resolution mirrorless to go with the Panasonic high-res body we already know about. Two new speed demons, if not three, will stalk the Tokyo Olympics in a year and a half. Fuji's promising the first 100 MP camera under $30,000 - and they're likely to get it in under $10,000. At least a couple of new video-oriented cameras are coming as well.
Hardly a time of no development effort - but nothing much in the Rebel/D3x00/a5100 range. Everything listed above is going to be $1000+, and very little of it (the Canon and Nikon speed demons, and the medium format Fuji, but that's all) will be over $3500.