Your argument is basically "it's too expensive". There will be more than
enough incentive for someone to develop a cheap, recyclable but robust
plastic that can be used for medical devices.
His argument is more that adding lots of laws will stifle industries and make it much harder for new, inventive products to be created, and that includes life-support systems and the like.
Having a ban will let companies get creative and build equally strong but
recyclable plastics. Nothing is impossible, it's just expensive. And if
we increase the costs on everything then it works to everyone's benefit.
A lot of the plastics that are used today are thermoplastics, because they're easier to build and manipulate- all you have to do is melt little chips and then squeeze them into a shape and you're more or less done. Things like HDPE- what a lot of plastic cutting boards and gallon milk jugs are made of- are really useful and strong in many use cases. Those
other use cases are where things like thermoset plastics- think stuff like epoxy- come in handy. There are many applications where nothing else, including metal, will work well, for various reasons.
Having a ban will let companies get creative and build equally strong but recyclable plastics.- you missed one of cr0sh's points- even if everyone only builds slightly different plastics, it's still hard to get a good fully recycled product.
And if we increase the costs on everything then it works to everyone's benefit. I don't think that that's how this works. I'm pretty sure that if we increase the costs of everything, then the overall cost of living goes up and money gets devalued, the only real difference being that the taxing body has more of your money. I don't think that this is a good idea.
Banning some particularly egregious chemicals (such as CFC's, which absolutely destroy the ozone layer) is a good idea. Saying no to a ginormous subset of plastics is a particularly damaging idea.