The model number for the TV is pv-m2047. The remote is rca model number rcr312wr. Is my TV just too old?

It's possible, but unlikely. I don't think Panasonic has changed their IR signals too many times in the past. Make sure you've tried all the codes. It could just be that the remote you're using does not have the programming available. You could try another remote. If you have the original remote working, you could pick up a learning remote.

If you have a cellphone camera, look at the IR as you press the buttons on remote, may not be transmitting.
You should see a white pulsing light.