You're on that again? Notice that every time you write about that it's one of the long-running Shonen martial-arts battle series? First Naruto, now Fairy Tail. What about all the other genres? A bit much to say all anime does that, when all your examples are in a very narrow genre that some of us don't even watch.
Mostly because I don't have the stomach for gore and blood... or for most series where there is a large population difference between genders. As well I prefer longer shows to shorter ones (18 episode animes are very common).
Also I've been in other genres and they follow that basic pattern as well.
Though if you want other series that do the same thing. Detective Q was pretty short and it didn't take long for every female character to be thrown under the bus, and it wasn't a show that involved battles.
Heck if we include shows where there is ANY form of competition, yeah they all fall under that unless the lead happens to be female (Dang that series tended to break a lot of my expectations... such as making weaknesses genuine weaknesses as well as making the character's strengths not factor in all the time).
Though if that is a challenge, I can attempt to prove the pattern correct. I still remember the general rules
1) The main character cannot be female
2) The cast cannot be majorly female
(The first is excluded because it is the lead, she is excluded like the Queen of England from the caste system. The second is excluded because that means the show has a female focus)
Mind you not that I haven't seen that happen in the second case...
There are three ways the anime can fall under this
1) The female character who was competent becomes incompetent or subservient in accordance to the focus of the show (Marchen Awakens Romance)
2) The female character's plotline is thrown out or forgotten about (Yakkate Japan)
3) The female character's plotline is solved by a male character (Fairy Tail)
Technically Prince of Tennis doesn't do any of those 3 (except maybe the second... ok the second) but it achieves this simply by making every female character incompetent by default and its general sexist attitude towards women and women tennis players.
Makes me glad i stay off of Shonen, i have only set im reading now that i can enjoy cause they can keep the battles around for upto 3 chapters without boring the hell out of me.
Honestly I am not sure how much I've seen is Shonen. Gundam is Shonen right?