And like I posted earlier,
https://www.eevblog.com/forum/beginners/bandwidth-calculation-caveats!/msg807413/#msg807413
And what does it matter?
Clearly, only signals with comparable waveforms can be compared with simple rules. (Duh?)
The circuit in my simulation has largely the same risetime, but reduced ringing/overshoot, if I tweak the frequency response to be softer: closer to a Bessel response, which will be more typical of oscilloscopes (e.g., Tektronix's famous vacuum tube distributed amplifiers from the early 60s). However, I'm more interested in the frequency response, so I want those extra dB of flatness out to the cutoff frequency, which introduces ringing without improving the step response much.
(What I find impressive, really, is those Tektronix amplifiers must've been good for 500MHz of gain-bandwidth! In tubes, no less! The reason they topped out around 100MHz, at the system level, is a combination of factors: intentionally softened frequency response (for clean step response), required cascading of stages (two 100MHz LPFs cascaded do not have 100MHz BW, but more like 70MHz -- and they needed 3-4 stages in the oscilloscope to get enough gain!), and needing gain at all, GBW being what it is.)
Tim