There's a difference between things you're expected to have to own the game in the first place and the means (or lack thereof) that games provide for you to 100% them.
So what you're saying is you put yourself through these things because you feel like completing every little task in the game despite no reward and no one requiring you to do so.
Think about that for a second. You're complaining over a problem you set up yourself because you decided to do everything available. You have no excuse to complain when the task is neither a requirement to progress in the game nor affects anything in the main quest.
Why is the implausibility of optional content any less objectionable than the implausibility of the content of the main game? As far as I'm concerned, you haven't
really gone through any game until you've at least attempted to 100% it. What fun is there in only completing the required quests? In my opinion, half the fun of a game like Pokemon comes from optional elements. If the optional elements aren't in any way fun (which is alarmingly becoming the case more and more with Pokemon), then why don't I have an excuse to complain?
If you don't feel like using the WiFi center, then go to Serebii, Bulbagarden, Pokecommunity, Smogon, Pokeani or any other video game site and find someone who can offer you what you want. This isn't that difficult if you're willing to do a little work for it.
You're kidding, right? Have you recently tried wading through some of those crapfests? You have to flood a request for a Pokemon before you even get a response, and when you
do get a response, they'll either want a shiny Pokemon, or an EV Trained one, or both. Now, if I have to EV Train a couple of extra 'mons to get at that Jirachi, then I don't mind. But when it's standard trading fare, something is wrong.
At this point, it sounds like you expect the games to hand you everything on a silver platter.
If by that you mean that I'd like it to be possible to actually obtain every Pokemon without resorting to limited events or migrating from previous games, a non-counterintuitive GTS, and a Battle Frontier whose NPCs don't cheat to win... then yeah, I guess I'd like it all on a silver platter.