See, its eco-theatre our generation will be remembered for. Fiddling around with plastic recycle while the planet burns.
[1] Right now, with cheap oil, that is.
It's more sustainable to throw away a plastic spoon that wash it. That's pretty plain - an individual has not optimized their process for cost and resource usage - they're just squirting randomly like 100X the soap it would take in a large industrial washer to get that spoon clean.
Efficiencies of scale are massive and irresistible. You cannot grow vegetables in your back yard at the same level of efficiency that big ag can, not even close.
You can't drive your individual car at anywhere the efficiency of a bus or train - we should all get on board that one, it makes sense to people. While somehow the other efficiencies don't. They just get mad when you point that out.
I think of it as a spaceship. We can argue about how expensive maintenance of the food recyclers, water purifiers and oxygen systems are, but that's really moot: we maintain those things or die.
We'd have to make the decision to stop the oil industry etc. before it matters though. Until then the marginal cost of 1 spoon is vanishing small, and fussing over it is spending time and effort on foolishness.
I'm not sure what planet you live on, but I live on one with a finite amount of oil. It also happens to be a planet with beaches where I've picked up hundreds, if not thousands of these "sustainable" plastic spoons, and forks and knives and bottle caps and bottles, toothbrushes, straws, bags, and one-use containers of all kinds.
So when people talk about it being "sustainable", I admit, I fantasize about dumping a few hundred bags of this junk right on their front lawn and seeing how much they enjoy it.
In contrast, I have not once--not once--picked up a metal spoon off a beach.