Such thoughts are provoked and informed by Break Point by Kevin Mitchell, a book subtitled the Inside Story of Modern Tennis, but which is more precisely a discursive, thoughtful and witty examination of the modern game by a journalist who is an entranced, and sometimes sceptical, follower of the ATP army.
Mitchell first set out to celebrate the big four of Roger Federer, Rafael Nadal, Novak Djokovic and Andy Murray but his purpose changed when all showed signs of fallibility.
Mitchell, in brief, then decided to give a snapshot of the game offering both gentle hints and strong opinions on where the sport may be headed. Mitchell is deceptively languid. His fluid writing style, however, cannot disguise his innate ability to ask the right question of the right person.
Mitchell is brilliant on the personalities; say, that Federer's greatness can divorce him from others, that Nadal's neurosis is a fuel rather than a spirit-sapping burden, that Djokovic is smart but almost impossible to know.
He excels in his portrait of Murray; the most convincing this observer has read. Mitchell has captured the Scot in all his shyness, dry humour and bluntness. His connection with the Wimbledon champion is perhaps helped by Mitchell being a boxing writer of substantial gifts and Murray being a boxing fan of considerable passion.
This connection has allowed Mitchell to peek behind the defences Murray puts up against intrusion.
The boxing beat also helps Mitchell understand tennis and the tension that drives it. Tennis has almost lazily been compared to boxing and there are similarities in that it is essentially a physical combat between two foes. However, tennis does not allow a physical demonstration of that in the manner of punches thrown.
It might be better for the psychological well-being of the combatants if it was allowed. It would dissipate some of the acrimony that builds up. The big four are not chums: Rafa and Roger are at odds over slow play, Roger has never been too keen on Novak, Rafa and Novak are far from buddies, Roger can be, well, quizzical about Andy. And Andy? Well, the Scot lives in a world where he is close to a few and perfectly polite to the rest.
The core of the book is how and why the big four dominate. And how long this cartel will reign. All four are physically extraordinary. They have all been dented by injury. Even the remarkable Federer, who has never walked off injured in a match, carries a bad back and other strains. But they all devote themselves to regimes that would daunt most others. They do this because they have to and because they can. All four have the resources to employ the best trainers, coaches and physios. They have worked to rise to the top. They work to stay there.
Mitchell finds wonderful raconteurs. Pat Cash, the former Wimbledon champion, is persuasive about the demise of Federer, though he may yet be proved wrong in a matter of days. But the most fascinating is Mats Wilander, the Swede who won seven grand slams in the 1980s. He is perceptive on what separates Murray from Djokovic. "Murray against himself would be an interesting match," he tells Mitchell. "Novak against Novak would not be so interesting because he is fairly one-dimensional." Murray has extraordinary variety to his game but the Serb's Plan A is regularly invincible.
So who can challenge the big four? Stanislas Wawrinka won the Australian Open this year and is still at SW19. Milos Raonic, too, is spoken of in praiseworthy tones and plays the winner of Simone Bolelli and Kei Nishikori for a place in the last eight.
However, the biggest noises are being made for Grigor Dimitrov, the 23-year-old Bulgarian ranked 13th in the world. He plays Leonardo Mayer of Argentina today and could face Murray in the last eight.
It could be the match of the tournament between two players who are intelligent, talented and keen to explore different strategies to win a match. But, as Mitchell observers, the big matches tend to be won by the big four because they are stronger in mind and body. His book is timely and judicious. The breaking point for the big four, though, has yet to be reached.
Break Point by Kevin Mitchell is published by John Murray at £18.99