I think one thing I agree in the argument with is that the skills in American football, a sport with an overall small number of involvement, are way of in advance of what we see in RU.
I must admit that I don't follow American Football at all so I cannot comment - that said have spent a bit of time passing an american football in a 'throw-about' with my wife's cousin in Canada when we visited last summer I must say I am in awe of the ability of American footballers to throw the ball with such speed and accuracy. Beyond that American football seems like a bit of a bundle to me - but that is my lack of knowledge.
Not sure how participation in American football compare with rugby union, suspect rather more play American football than we might think as it isn't really in our psyche. But that isn't the only issue. It isn't just overall numbers but whether a sport is a minority sport or a predominant sport, meaning that the sport will attract a lot of the available talent (as most athletes tend to be good at a range of sports but need to opt for one professionally). So for American football it is a major sport in an major country (the USA - a country of some 300 million people). That contrasts with rugby which, I'd argue is only a major (or perhaps the major) sport in New Zealand, a tiny country. Nowhere else is is other than a minority sport - and that (despite all the coverage) includes Wales (with far more people playing football), South Africa, where rugby remains a major sport only in the white minority and Australia.
And interestingly that contrasts with cricket - globally a minority sport - but is huge in several countries with massive populations (India, Pakistan) - now currently the infrastructure limits development but the potential is massive. Rugby, by contrast, is very limited in terms of its development.
