physios (and all other folks) that fly with you. first class and private flights (hilarious that the top players are flown on the tournament dime to the tournaments), perfect nutrition (potentially with personal chefs), nutritionists, drugs or drug therapies, surgeries, preventative medicine etc. staying in a topnotch hotel for two or three weeks prior to a grandslam tournament to get accustomed to the location and time zone.... the list goes on and on.
federer can spend 5 million on it per year without notiicing it. the world number 100? probably 20k.
Sport should be more about individual qualities of the sports-man/woman than about money buying them some more advanced technology.
The costs to have a F1 is incomparable. Any single part alone is astronomical and many have to be changed between races. Having a car at all for training is a miracle!
the racket and shoes don't matter in terms of expenses, at all. RF's cost is in the millions and you are comming up with rackets... he is drawing a completely unfair advantage that only maybe 3 or 4 other tennis players can afford.
thats like saying the F1 team only needs to purchase tyres.
did it kill the tennis sport and/or is it killing the sport? you could argue that way given that it is always the same folks winning the big tournaments