If the $5 billion is a random number assigned to 8 corvettes or less, I would agree. Go for newer equipment.
But if one is talking 12 to 20 corvettes, with only $5-billion Canadian to spend, then if one cranks the numbers, it really does become very very clear that it is not possible to buy much newer equipment unless the corvette is downsized to almost patrol boat functionality. In such a $5-billion Canadian dollar spending cap, re-using old equipment is really the only realistic way to arm the warships.
I guess we will need to wait to see how this (both requirements and budget available for the corvettes) unfolds.