They were an idea, not necessarily bad in theory, which was, I believe, from the Gnu folks. However, it seems that like much Linux documentation (and to be fair, at times, other docs) the people got tired of the idea in the middle and stopped.
There are some exceptions--ls is an example, where the info page is actually more detailed than the man page, but much of the time, if you go to the info page, you'll find that it's simply a duplicate of the man page with somewhat different formatting.
So no, they're not obsolete, even in Linux.
If I might, with no sarcasm, make a suggestion from my own experience--if you're used to BSD and are now in a Linux job, you can rant against it and let it tick you off, but it's self-defeating and will make you unhappy. You're better off looking at the advantages---more manufacturer hardware support, Flash 9, the fact that it's quicker to install rpms or use apt than it is to install from ports and the like, and then just concentrate on the applications.
Much of the time, that's where most of your work will be done, and working with say, postfix in Linux is like working with it in BSD.
Yes, when you're used to what most of us here consider the more logical BSD layout, the lack of bloat, etc., it can outrage you, but in the end, if your job is Linux, then you might as well enjoy it. Spending much of your time thinking, "This is horrible. WHY can't they use BSD?" is only going to make you grouchy.
You might even find, as I have, that it becomes like a family member of whom you're not all that fond--it's OK for you to insult it, but when other people do, you feel almost obligated to defend it.