Why is the "VE-D" number nowhere near the original 95% efficacy number widely reported for the Pfizer/Moderna vaccines when they were originally approved?

Is it different methodology or is it changed nature of the pandemic?

Thanks for the link. There are also graphs for mortality, that show that vaccines continue to greatly reduce the probability to die of COVID-19: https://www.science.org/doi/10.1126/science.abm0620#F3

Combined with the reduced probability to get infected, the only thing you have to worry about is infecting the unvaccinated.

A rapidly evolving virus rapidly evolved, to the surprise of no one who paid attention in biology class.

I wonder if covid conspiracy folks also think influenza is a "happy accident" by the pharmaceutical industry.

These graphs don't quite tell me enough. It's a complex problem and even with margins of error for varying health condition I'd expect at least a 3d projection to be required to map between age, time (since 'full inoculation') and risks of illness / disease / hospitalization / death.

I have also heard that lifestyles which encourage sitting all day and correlate strongly with lower fitness and higher carried fat are increased risk factors.

I guess I'd appreciate a formula from the FDA and CDC that tells me roughly what time frame they recommend a (regular interval?) booster shot, rather than some oversimplified coarse number.

It's called Product-Market Fit.