Starting with the original 6 Mpix Digital Rebel I lived professionally off Rebels for eight years until I stepped into the 5D world where I now use the SR, the IV, and the III. In fifteen years we have gone from 6 mpix to 50 while acceptable ISO has gone from 200 to 6400. Frame rates have gotten way higher. Our cameras have become vastly more capable and we have surely benefitted from that.
While I understand that the forum denizens here are knowledgable and passionate, occasionally I feel there is a bit of tech snobbery evident here: "Oh my God! Canon is still selling stone age 18 Megapixel cameras! The horror of it all! And the horrendous kit lenses... Canon is doomed forever..."
The T2i and T3i were my two 18 Mpix go-to professional use cameras for a few years. With battery grips, 580EX IIs on top, mounted with a 17-55/2.8 and a Sigma 50-150/2.8, no-one accused me of imitating a professional while using the same camera Uncle Freddy had. And with careful work on my part, my customers always seemed happy with the quality of my pictures. I have 15 L lenses, 10 of them white, many from my film days. Coupled with my various 5D cameras I have the top rate tools to produce and deliver work of the highest technical quality. And I do pixel-peep!
Yet the vast majority of my non-assignment pictures over a number of years now have been shot with a (lowly 18 Mpix) SL1 (recently replaced with the SL2) and the three plastic mount kit lenses; 10-18, 18-55, and 55-250 (all now STM), as well as a nifty fifty (originally also plastic-mounted.) And that rig has produced outstanding pictures. These lenses are very, very good! They might be plasticky, they might have a bit of distortion, and the sharpness may fall off a bit in the corners, but they sure represent by far the best bang for the buck in all the photo universe. I recently shot the same scene with the SL2/55-250 and the 5D III/100-400 L combinations. The photos were nearly un-dishtinguishable. Given that the first rig can be had for $ 700, and the second cost me (some years back) $ 4,900, I say Canon is doing a bang up job!
Since I am clearly not privy to Canon's strategic thinking, I cannot say what the intended market for a 4000D might be. But I certainly feel that when you get a person away from the cellphone wide-angle lens and into an APS-C camera with a quite good zoom they will absolutely like their pictures a whole lot better! And if Canon can sell cameras using fully depreciated tooling and components I think we will all benefit in the long run.