Since I mentioned tennis before in another thread and it is Australian Open season...
Lets say an average tennis set is 10 games (6-4) and each game is 6 points. Some are longer, some are shorter.
If you only shoot the serve of every point and you shoot for (say) 2 seconds then at 12fps that's 24 frames per point, 144 per game or 1440 shots per set.
A woman's match is 2-3 sets long (2880-4320) and a mens is 3-5 (4320-7200). Of course there are outliers.
Halve the numbers if you only shoot one end. Increase the numbers if you shoot in-point.
A grand slam tournament runs for 14 days (Jan 18 - Jan 31.)
Then on center court there is typically at least two mens and three womens matches per day ....
Numbers are now 8640-12960 + 8640-14400 or 17280-27360.
... for the first 8 days: 138,240 - 218,880
... from day 9 on, the numbers of singles matches (which most people care about) starts to drop, maybe 14 matches (7 of each men and women) across 5 days... 20,160 - 30,240 and 30,240 - 50,400.
Total: 158,400 - 269,280
If you only squeeze the shutter for 1 second instead of two then that brings it down. If you don't cover every match, that also brings it down.
And that's just from one camera. Some have multiple cameras (mounted courtside and connected to your laptop via ethernet or WiFi plus the camera in your hand.)
Or to put it differently, one shutter per camera per tennis grand slam tournament.
Now on to buffer...
If you're shooting both ends then you're moving your camera between ends in less than a second (at men's serve speed (140mph+ - 205+fps, tennis court 78 feet long), the ball gets to the other end in under half a second.) I don't know if you can swing a 1DX + 300/2.8 back and forward that quickly.
If you're only shooting one end then the ball is back at "your end" in about a second, so you're doing 10fps per second. The only choice here is to shoot JPEG - a buffer depth of 180 gives you 18 round trips for the ball (something which almost never happens.)
All of this assumes 'blind shooting' where you don't know what is going to happen each time the ball is at your chosen end of the court but the cost of taking the shot ($0) and the inconvenience of dealing with so many pics is far outweighed by the cost of missing the "money shot" for that moment when the player slips, etc, so you're already shooting before the "money shot" happens.