Classes are not solo only

[Akumu]

It's not that jobs can't solo, they just lose their safety nets. It's not that classes can't join and be effective in a full party, they just have safety nets for less damage output. They each bring their own strategies to the table.

Classes and Jobs are two different ways to level(Horizontally or Vertically). Switching to one or the other just gives you an edge in different situations. That edge can easily be made up for with a different approach to a situation.

I prefer jobs over classes myself. That's because I have a longer history with them which is why(I assume) most here has never looked back at the classes.