We got about two seasons out of Adam Jones, and not even as a nailed on starter. No-one seems to complain about that not being enough.
If where we are at is that we are relying on the academy to give us the next generation of locks, but they are not fully baked yet, then having a very experienced international to help shepherd them through is not such a bad plan, as long as the contract is appropriate for the number of games we are likely to get out of them.