Its still a crap explanation form me and I do apologise for that. 4 hrs sleep in 36

TJ, I understand the gist of the explanation OK.
It's just that the cycnical side of me just sees 29" wheels/tyres/forks/framesets as an added retail opportunity rather than an appreciable advance in bike ergonomics 😉

If it was that obvious surely someoine would have 'come up with it' a bit sooner ??

Well… work done = force * distance

I'm pretty sure it ends up being more energy for the big wheeled case…

😕

then why does no one make a 32" wheel

There's an optimum length for the wheelbase otherwise the bike would handle like a barge. Would have thought 29in wheels would be the max you could fit without having to stretch out that wheelbase.
Other problems would be toe overlap – esp. on smaller frame sizes.
Big wheels roll better – but given that people don't ride in straight lines and ride at variable speeds over different kinds of terrain it becomes a bit more complicated than bigger is better.

This is a picture of my 29er. It is fast on the flat and just seems to keep going. In the snow it was 100% better than my 26 mountain bike as it just seems to grip.

Handles like a gate though.