Why would that make them bad? They're still good. It just isn't clever to rely only on one source of power. It is like chicken being a good thing to have in the fridge. That doesn't make a sack of potatoes in the cupboard bad.
On a 1:500 year time horizon we know there are threats that dim the sun (possibly quite a bit shorter now that nuclear weapons are on the table and we seem to be incapable of dealing with that threat productively - the number of actors with nukes is growing). Planning for that isn't anti-renewable, it is just cautious.
And nobody was talking about K-Pg events. You'll notice the years quoted were all after the Roman Empire was founded.
