The Canon EOS 4000D and the Canon EOS 1300D seem to me to have the same specs and mount the same lenses, but the second one is cheaper. Is there any risk in buying a camera which is going to go out of market soon? Since you can mount the lenses of the new one, I can't see any risk. What am I missing?
TL;DR: There is no risk in buying older generation Canon body.
Canon is known for the consistency of lens mounts and compatibility. They have 3 mounts for photography right now, 2+1 actually.
- Oldest EF mount for fullframe.
- Younger EF-S mount for crops.
- Youngest EF-M mount for mirrorless.
EF lenses can be used on EF-S bodies directly, not vice versa! Other combinations are possible with proper adapters.
Both your bodies use EF-S mounts so there is no risk at all by using the older body. If I read the Canon designations right, the second one should be higher tier body (when same generations are compared) which compensates the differences in running-in and running-out bodies (when same tier is compared).
In other words, new EOS 1xxxD should be slightly better than EOS 4xxxD. It is possible, that the 4000D is slighty modified 1300D design, therefore the same specs.
Actually, old Canon FD mount lenses are directly mountable to EF and EF-S mount with only one drawback - there are no pins co connect to the body and camera thinks there is no lens mounted. It will work, but in all-manual mode (the lenses also lack motorised focus and apperture settings)
In the past what you could have missed would have been significant technological progress: better AF, better sensor, support for video, WiFi, Bluetooth, ... But progress is leveling off and there are less differences between camera generations now. To some extent cameras reach their end-of-marketing-life when they are at the lowest prices that their manufacturer is willing to sell them for, so they are a bargain at that point.
The Canon 4000D has lower specs, and perhaps worst of all, a PLASTIC lens mounting interface, rather than metal. I assume their expectation is that the vast majority of users will leave the kit lens on at all times. If you expect to use multiple lenses, the plastic mount will not have the same longevity.
As far as I can tell, the only difference between the two is that the 4000D has a slightly smaller screen than the 1300D, which makes it slightly lighter. As the weight difference is insignificant, this to me means that the 1300D is better.
What am I missing?
At a complete guess, if Canon are indeed replacing the 1300D with the 4000D, then they're trying to make their bottom of the range camera less appealing, in order to encourage more consumers to stump up the extra cash for the next level camera.
So buying the older 1300D while it is still available seems like the better option.