Attenuation in the circuitry of differential vs isolated probes
Kevin White on StackExchange states:
It is non-trivial to perform [analog] isolation and maintain good high-frequency pulse performance all the way down to DC for an analog signal. So [...] it does come down to cost, and who would pay for it.
[...] these days I would be very tempted to digitize then isolate. But even that would be non-trivial to achieve the 50MHz+ BW with good pulse performance (the article linked indicates that the probe has 50MHz BW). That might require 250Ms/s at say 8 or 10 bits so we are up to 2.5Gbps to be transferred over the isolated link. Together with power and synchronization signals in the other direction. That is starting to get complex. At kHz rates it would be fairly trivial these days.