History argues against that.
2012 - $2,099 FF 6D has a polycarbonate body, bare basic entry level Rebel AF system, 100,000 cycle shutter durability rating, low pixel density 20MP FF, etc.
2012 - $3,499 FF 5D Mark III has magnesium alloy body, 1-series class AF system, 150,000 cycle shutter rating, low pixel density 23 MP FF, etc.
2014 - $1,799 APS-C 7D Mark II has better build quality than $3,499 5D Mark III and is almost the equal of the 1D X in build quality, has a 65-point all cross-type AF system very similar to the 61-point (41 cross-type) AF system of the 1D X and 5D Mark III, a 200,000 cycle shutter (compared to the 1D X 400,000 and 5D Mark III/IV 150,000), high pixel density 20MP APS-C (50MP FF pixel density), etc.
2016- $3,499 FF 5D Mark IV has equal build quality to 7D Mark II, 61-point (41 cross type) world class AF system, 150,000 cycle shutter, mid-density 30MP FF sensor.
2017 - $1,999 FF 6D Mark II has polycarbonate body, 45-point 80D class AF system, 100,000 cycle shutter, mid-density 26MP sensor ,etc.
It's entirely reasonable to expect an APS-C R7 to have magnesium alloy body, top-class AF system, long-life shutter, and high pixel density APS-C sensor for less than the R6.