Thanks for your replies guys!
Some of you guys misunderstood my post (or I wasn't clear maybe

).
I'm not complaining about the box adv. lying to me: what is says is true (less leveling, less farming). I just did not understand when I read this that this wouldn't solve the problem of time spent on the game, as explained in my initial post.
And I'm not complaining about the fact that it takes time and practice to become good, that's fair enoug.
I just started to think that I cannot do well in pvp without spending several evenings a week playing plus some time at the weekend and I am afraid I cannot play so much.
At the present time, my situation is not SO bad. I have unlocked most mesmer skills and many elementalist skills with my PVE character. I played my mesmer a lot, I think I know much more than an average player on mesmers and probably more than an average mesmer. I have some pretty good builds as well.
I was invited by some good guilds or PUGs sometimes and I am currently in a decent guild (rank about 100) and trying to get into another one that would suit my needs better.
My problem is that my guildies don't like the fact that I can play only mesmer, so I had to diversify, using faction to unlock skills for a prot monk and for a curse/death necro. The curse/death necro seems pretty straighforward to me, but I have no clue as to how to play the prot monk. Quite understandably, I would need practice to play them well.
Same for my mesmer: I have some nice experience with my mesmer (about 300 fame) but this game evolves so fast that I need to keep informed of the new trends, what are expected from mesmers to fit in good groups and counter the new trends, etc.
In short:
I have come to think that I cannot do well in pvp if I do not play at least a couple of hours, a couple of times a week. Even more, I am afraid I will never be considered as a reliable guild member if I cannot log in every night, as people will make their builds without me if they are not sure I will be there any time they need me.
For example, in my current guild, I have not been invited in the last 2 weeks because their current build includes 5 rangers and 3 monks and I play non of this.
Other game, same problem it seems.
notra