What trust model are you thinking of though? Because another way to look at it is that Apple has pushed an update to ensure these apps keep working and remain secure.
And this is part of the agreement between an app developer and Apple; for a long time now, a developer doesn't upload a full compiled app to Apple, but a package containing partially compiled (itermediary language) code and assets for many different platforms and resolutions, leaving it up to Apple to do the final assembly based on what device it downloads. This allows them to (re)compile for newer hardware, 32 vs 64 bit CPUs, save bandwidth and storage space by only having the device download the assets for its device (and for e.g. games the assets for the level they are playing at that time), etc.
So again, what trust model are you thinking of? Apple is a trusted party when it comes to this, I'd even argue they're more trustworthy than the app developers themselves.