It comes down to matching the tool to the job.
If you are elk hunting in an area where a 100 shot would be long then by all means take the 30-30. It will work as good as anything.
If you are hunting elk where the shots could range from 0 to 400 yards then take a more powerful cartridge like a 30-06 or 300 win mag.
If you are like RR and prefer to hunt in an area where you could take 500 - 1000+ yard shots then take an even more powerful cartridge still. Something like a .338RUM, .338 Lapua, .300 RUM.