>The alternative to regulation is innovation

That's a very easy but hand-wavy thing to say.

How exactly would your suggestion work? Are the companies supposed to share their findings from this forced research with the world? What happens if they happen to discover something that doesn't help with the plastic problem but does improve their bottom line somehow? I can't see this functioning in any way whatsoever.

You don’t need to impose R&D to them. You can tax them and funnel that money into R&D labs/companies tackling recycling.

Another alternative is anticonsumption; stop or reduce use of disposable packaging if possible.