As far as I know the virus H1N1 itself didn't really evolve in the sense that it got milder - all hosts either developed immunity or died off. Now our immune systems encounter one of the endemic, seasonal strains of H1N1 when we are young (or we get a flu vaccine) - however from time to time a new strain of H1N1 emerges that is dissimilar enough, see e.g. 1977 flu or the 2009 flu outbreak.

What about the original SARS?

The original SARS had a much higher mortality rate, which meant that trace-and-isolate responses actually had a chance of working. The mortality rate of Covid-19 is nowhere near that of SARS, which actually allows it to kill more people in the end because it can spread stealthily, and no lockdown or trace-and-isolate has worked. There are also more reports of animal reservoirs for Covid-19 than for SARS.

It also didn't incubate the same way

SARS really seems like a bullet we should be lucky we have dodged

No, it was never possible for original SARS to have r0 comprobale to nCov19. However that was the fear from the start.