The guy casting resurrection is not a high level Cleric. He is merely an NPC that can cast this ritual.
And how did said NPC get powerful enough to cast this ritual if he didn't adventure, and where can my PC get in on some of that action? Bang goes your world's internal consistency...
That's possible, but you're not selling stuff to your antagonists.
Who says they're antagonists? They certainly could be at some point, but it's not cast in stone. Hell, somewhere down the line they might even be friends of ours.
The local mercenaries might simply not have these aforementioned +1 scale mails.
Of course. But then again, they might. Random chance; roll the dice.
This doesn't have to be a default assumption. There are no adventurers guild in Lord of the Ring.
LotR, while a wonderful setting for the books for which it was intended, is not at all an ideal setting for an RPG - unless, of course, you intend to RP the main characters in the books, in which case you're absolutely hidebound by canon.
Look rather at settings designed for D+D. FR has adventurers chasing all over the place. Greyhawk ditto, only slightly further in the background. Ditto the Known World (later called Mystara). Dragonlance is an oddball, in that while designed for D+D it also suffers from the canon-uber-alles problem found in trying to use Middle Earth.
One setting in which it *is* practical to assume the only adventurers in existence are the PCs is Ravenloft; assume all the others got turned into the vampires you now have to kill...
Taking this PCs-are-special to its logical end conclusion raises a question: if I'm running a character in a game where we in the party are the only known adventurers, and my character permanently dies, where does my replacement come from? And, how did it earn the levels it has when it comes into the party? As soon as you answer "by adventuring", you've just shown there are other adventurers out there...
Best to just tell the players up front, right when you drop the puck on a campaign, that they are not the only fish in the sea; and that some of the other fish are mighty big.
Lanefan