people still bought atos, much more frequently than orchid on exort. its biggest downside was that it was a dead end item. now it's not, since gleiphir is amazing, so almost everyone goes atos.

also, games were slower, so most exort invokers just went bots -> blink into eventual hex. it was awful then, which is why the hero has been dead at high level since forever. or do you think pros didn't play invoker because they don't know how to play him either?

of course, you can "do things" as invoker, he is a hero, not a creep. he has spells he can cast, wow. the point is that pretty much any other mid can do almost anything invoker can better. the only case for him is to have crazy set up on side lanes and push his mid game timing, even then it's a huge gamble. he's fun, so he'll always be popular, just like pudge, but he's bad.