Nature does not have above normal temperature. And I think article talk about the also degrading when just tossed to nature...
Bottles don't carry themselves to solar-powered furnaces. If we assume that they did (and plastic oceans in the pacific demonstrate otherwise), then we could target the much-easier problem of making plastics that are stable when dumped in a landfill.
That way the lifespan of the contents wouldn't be limited by the bottle - minimising food waste - but we'd retain the ability to get rid of the bottle safely without huge landfills.
Depends on how much you dig I guess?
I wish.