I would hope that you came to this realization through the process.
After climbing the mountain to get enlightenment the answer to the question:
What is the "Ultimate Supertelephoto for Travel"?

You would now come to the realization that when it comes to the big white lenses there is no universal answer for all.
The white lenses are all the "Ultimate" and the right one is the one that fits your needs the best.


On another note, I hope you do not tip over often in your kayak. If it were me in a kayak I would be looking for floaties for that 500mm.