Totally agree with the OP. Too much emphasis is placed on the Olympics as an indicator of who is the best. Is it the biggest single meet in the sport? Yes. But at the end of the day, it is just one meet. Think of the many things that can go wrong that are beyond the realistic control of the athlete. An untimely viral infection, an unexpected injury, living in a country with unpredictable selection criteria, etc. Hell, even a loud noise in the middle of the night that jolts the athlete out of deep sleep two nights before the race could be the difference between feeling great on race day, and feeling sluggish. True that all the athletes are trying to peak for the OG, but that doesn't mean that one race (or set of races including the semis) can really determine who is the best runner. For example, would anyone deny that Asbel Kiprop is the best miler in the world? Yet his WC/OG record really doesn't reflect the reality that he is the most talented and dominant miler of the last 2 Olympic cycles. A slightly different example is Mo Farah. I will concede that he is the most dominant 5/10K runner since 2011. But, what if Mo lived in Kenya or Ethiopia and had to contend with a dozen other runners every year just to make it to WC/OG. In that setting (without the convenience of only needing to peak once a year), would he really have won the 9 golds that he has won since 2011. I'm sure he would have won some golds, but I doubt he would have the perfect WC/OG record that he has had since the 2011 WC 5K.
I think a much better format for determining the best runner would be a diamond league type of series where the diamond league final is considered as prestigious as the world championship meet. I wish this type of "season" approach could become the greater focus with athletes instead of the "one-off" approach of the current WC, OG system. A "season" emphasis would give enough chances to race for all the random variables to be balanced out.
The "season" approach is undeniable the best approach to determine the best athlete (assuming the "season" is recognized as the preeminent competitive event). What if MLB, NBA, or NFL decided to have one big single elimination tournament every 4 years to determine the best team? Would anyone really think that was a reliable way to find the best? Yet we let the OG hijack our sport every four years and rob us of building any real momentum or growth in the sport of T&F. All the sports that are self sufficient have a season type of approach. Tennis and Golf don't need the Olympics because they have enough big competitions every year to give them an almost year round criteria for ranking the best athlete. The WMM has done a similar thing with the 7 (or 8) yearly Marathons that are all recognized as part of the continual competitive process. Many of the smaller sports (wrestling, gymnastic, T&F, etc) think the OG keeps them alive, but I think that without the OG, the governing bodies of each sport would be forced to design a real season/championship type format to maintain public interest/revenue. In reality, I think the OG are leeching of the many sports that could build themselves into something much better without it. I know it is unrealistic to wish the OG would go away, but we all have our dreams, don't we?