We have the same guarantee about that today as we did a month ago before this was announced. Apple writes the software that runs their devices, so they’ll always have the option to ship something like that.

Apple could have quietly implemented CSAM scanning server-side, and left the door open to it being quietly exploited in who knows what way. But they didn’t: instead they put a whole bunch of infrastructure in place that all but guarantees that they’ll be immediately caught (and publicly excoriated) if they try to use this CSAM mechanism for anything other than CSAM. (See the PDF that GP linked for technical details on why.)

Of course, they could still do it with some other mechanism. But in that case none of these CSAM changes are at all relevant to the concern, as that risk is unchanged from a month ago.