If it makes you feel any better, I was playing an inhuman amount at the time...and in the upper 40's I was still pushing a week per level. (Lower levels were quite a bit faster than that of course).
That was a long time ago

compared to now the game would be almost unrecognizable.
As far as now goes, it all depends on how long till the first expansion is released.....if it is say...9 months or so, then Folks could pretty much advance as far as they can advance in all 3 spheres by then....but not very many folks. I mean less than 1% of folks here. You'd have to be able to spend an enormous amount of time with the game, and you'd have to *want* it. There are loads of folks who play fairly hardcore who just don't like to craft or won't care to go through a ton of diplomacy (even though both systems are quite enjoyable imo).
Will it be possible? Yes, I expect so. Will many people achieve it before the first expansion? Nope.
Fear not. The game will have a long enough curve. It starts up easy then curves up and keeps going up till you wonder just how steep it is gonna get

There is no lack of content either.
Nobody will get to 50 and have seen everything there is to see in the Adventuring Sphere, I promise. There is just too much there to do.