In current machines, that's way off depending on how you choose to count "1 CPU instruction" for the metaphor.
Take Apple's latest laptops. They have 16 CPU cores, 12 of those clocking at 4.5 GHz and able to decode/dispath up to 10 instructions per cycle. 4 of those clocking at 2.6 GHz, I'm not sure about their decode/dispatch width but let's assume 10. Those decoder widths don't translate to that many instructions-per-cycle in practice, but let's roll with it because the order of magnitude is close enough.
If the instructions are just right, that's 824 instructions per nanosecond. Or, roughly a million times faster than the 6502 in the Apple-II! Computers really have got faster, and we haven't even counted all the cores yet.
Scaling those to one per second, a RAM fetch taking 100ns would scale to 82400 seconds, which 22.8 hours, just short of a day.
Fine, but we forgot about the 40 GPU cores and the 16 ANE cores! More instructions per ns!
Now we're definitely into "days".
For the purpose of the metaphor, perhaps we should also count the multiple lanes of each vector instruction on the CPU, and lanes on the GPU cores, as if thery were separate processing instructions.
One way to measure that, which seems fair and useful to me, is to look at TOPS instead - tera operations per second. How many floating-point calculations can the processor complex do per second? I wasn't able to find good figures for the Apple M4 Max as a whole, only the ANE component, for which 38 TOPS is claimed. For various reasons tt's reasonable to estimate the GPU is the same order of magnitude in TOPS on those chips.
If you count 38 TOPS as equivalent to "CPU instructions" in the metaphor, then scale those to 1 per second, a RAM fetch taking 100ns scales to a whopping 43.9 days on a current laptop!