Don't know if it's normal, but that's what I was finding when I was considering a trip in August. (ex Denver) Where are you flying from?
You're right, tickets to B.A. or Santiago are a lot more $ than tickets to Europe. Part of the reason we ended up using our FF miles for a trip to Buenos Aires in the fall (non-skiing) - 50,000 miles for the equivalent of a $1100 ticket is a lot better than burning the same miles for a $500 ticket to Europe.
I don't think you're getting Europe for $300 though (your fare comparison) That $300 you mentioned might be what the flyertalk.com folks refer to as $300++ where the + signs are taxes and fees - easily adding another couple of hundred. Lufthansa is notorious for advertising wicked low base fares (which is how Travelocity and some others display fares) and dumping all sorts of other charges into tax+fees until you end up higher than some other airlines' supposedly more expensive fare.
Check Delta's fares again. I've been spot-checking the actual ticket pricing lately just in case the miles-vs.-dollars equation changes to make it worth re-depositing the miles and buying the tickets. Delta was pricing out about $200-300 less than everybody else, down around $800 ($907 all-fees-in) when I checked a few days ago (that was for November dates so not what you want, but a drop from the $1100 originally). Of course Delta's pilots are taking a strike vote and if they strike, that's the end of the airline since management already said they'll liquidate it if the pilots walk.
It also looks like Buenos Aires is cheaper from the States than is Santiago, Chile. However more skiing is closer to Santiago. You may be able to separately find a cheap ticket from B.A. to your destination near the ski areas, from LAN or Aerolineas Argentina and overall make out cheaper.
Keep shopping the ticket price - you may find some other airlines dropping price to match what Delta is doing. Or buy the DL ticket and just take the chance on that new $50 standby requirement that requires other airlines to honor on a standby basis for $50 fee, tickets issued by an airline that ceases operations. I have a funny feeling that may be how we're going to Argentina!