Where do you draw the line?
Why doesn't the farmer have a "destiny" to be a good husband, a good father, raise children and teach them right from wrong, and live a good life? Isn't that a destiny? Well, then, he gets a raise dead too.
OK, if that's too much of a stretch for the "Must have a destiny" rule, then surely a king, or a high priest, or a leader of a guild of thieves, surely guys like these have a destiny? Guys like these have bards singing songs about them, have thousands or tens of thousands of people who know them and revere (or fear) them. Surely they have enough destiny to be raised?
As for me, I don't see the need for this silly rule.
Raising the dead needs no "destiny" at all. It never has, and never will, require destiny.
In my 3E game, you can raise a farmer from the dead if you want to.
So, you ask why everyone doesn't live forever?
Simple:
1. Raise dead costs a lot of money. The gem is expensive and casting the spell destroys the gem. Want to come back? You better be wealthy. This is why farmers and goatherds and barmaids never get raised - they can't afford it and they almost never have a wealthy relative or friend who will pony up the cash.
2. Raise dead requires a relatively intact corpse. There are many ways to die that Raise Dead can't fix. The better versions of the spell are harder to find (how many level 18 priests are there in the world, anyway?) and more expensive, so they are out of the reach of just about anyone. If you die to dragon fire, or acid, or get eaten by a hungry ogre, you better be really rich and very well connected to know someone with the right spell and be able to pay for the component.
3. None of these spells handles aging. Even the wealthiest king in all the world, with dozens of epic priests running around eager to True Resurrect the king in a moments notice can die of old age. You don't come back from that. (Maybe this is a bit of a house rule - I haven't read True Resurrect in so long I don't remember if it "cures" old age or not, but it doesn't in my campaign).
4. Heaven (etc.) is very nice for just about anyone. No matter which god you worship, when you die and move on to that god's realm, you tend to be happy you got there (not always true for those foolish enough to worship vile evil gods, though if they serve those gods well, their afterlife is pretty cushy too). Some people just don't want to come back once they sample the afterlife. This comes fairly close to "having a destiny" - if you cast raise dead on someone, they can refuse it; many people do refuse it unless they feel they have a reason to come back, such as fulfilling a destiny. (note: this is why PCs can't just kill the villain then resurrect him for interrogation - he will almost always prefer his afterlife to being resurrected and tortured, then probably killed again anyway - even if the PCs don't plan to torture or re-kill him, he will expect them to do that, or imprison him, and will refuse the resurrection).
5. There are ways to capture a soul. A captured soul cannot be resurrected. The magic needed is not really much harder to come by than the magic to cast resurrection. Therefore, an assassin who kills a farmer will probably just stab him, or poison him, or maybe decapitation (raise dead won't work in this case) - that should be enough. But high-level assassins who take contracts on wealthy merchants, priests, nobility, royalty, etc., will usually plan ahead with soul-capturing magic (it's all covered in the fee they require to take the job). Thus, the assassinated king cannot usually be resurrected until the soul is freed from its imprisonment - this can be a truly epic quest indeed, if the assassin is resourceful enough (and any assassin who accepts a contract on a king better be very, very resourceful indeed).
6. Story reasons. Maybe he's a ruthless tyrant king and the only church around with priests high enough level to True Resurrect him from the assassin who stabbed him and dumped him in a bag of holding full of lye refuses to do it because he was hated and feared. Maybe in some other story, the priest casts the spell but the god refuses it because the dead guy lived a life that is against the ideals of that god's faith - no resurrection for the wicked (or no resurrection for the wimpy, scholarly sage if you ask a priest of Kord to cast the spell). There can be bazillions of reasons to have the priests refuse to cast the spell, or have their spell fail due to godly whim, all justified by the existing story. You can even incorporate long arduous quests to raise a dead party member - the only churches in town won't resurrect your dead rogue becuase he's a kinda vicious guy so you have to quest to some far away church in a far away land to find a priest who appreciates your rogue's viciousness enough to raise him.
Summary:
In order to be resurrected, you need to be fairly wealthy and fairly well connected to know someone who can cast the spell and be able to pay for the component. Otherwise death is permanent.
And you need to die a clean death with an intact recoverable corpse, or you need even more wealth and connection to pay for the bigger spells' components. Otherwise death is permanent.
If you want to live forever, you also need magic to counteract aging, or one day you'll die of old age and be beyond any hope of resurrection.
And even you can afford it and can find someone to cast the spell, you just might like your afterlife enough to refuse the resurrection even if it is cast.
Assassins who take contracts against victims who have enough wealth and connections will come prepared to capture their victim's soul to prevent resurrection.
Given all that, I don't see why we need arbritrary and silly proclamations that raising the dead requires some mystical "destiny" at all.
