As others have pointed modern processors are three orders of magnitude faster in terms of clockspeed than processors from back then. There's also the fact that modern processors do a lot more per clock than this guy: using 64-bit wide datapaths, and executing multiple instructions every clock cycle rather than taking multiple clock cycles to execute an instruction, and having multiple independent cores. One rule of thumb is that your performance tends to increase with the square root of the number of transistors you use so you'd expect another 3 orders of magnitude increase in performance from the 6 orders of magnitude more transistors, for a modern chip being 6 orders of magnitude faster at executing some algorithm overall (if there's a normal amount of parallelism to extract).
Now, normally you have to worry about increasing clockspeeds having diminishing returns, since memory latency remains constant despite a faster CPU clock. But anything that could run on the amount of RAM the 6502 could handle would fit in a modern processor's L1 cache, and the scheduler is perfectly able to hide L1 latency so I think ignoring this factor is fair in this case.
Now, normally you have to worry about increasing clockspeeds having diminishing returns, since memory latency remains constant despite a faster CPU clock. But anything that could run on the amount of RAM the 6502 could handle would fit in a modern processor's L1 cache, and the scheduler is perfectly able to hide L1 latency so I think ignoring this factor is fair in this case.