It started to make me wonder: Why are these products still seen as novelties? We're constantly reminded that we've produced millions of tons of plastic that will take 1,000 years to decompose and are clogging our oceans, so surely there's more than enough of this stuff on the planet already to make all of our products for the next century. Why don't we just make everything out of recycled plastic? The answer, I found out, can be chalked up to a mix of technological, marketing, and cultural barriers. But there are some very smart people working to break these barriers down.

A few months ago, I committed to making more ethical purchases, particularly when it came to environmental sustainability. Naturally, Google and Facebook's algorithms noticed my new lifestyle and immediately began surfacing ads for shoes made of recycled grocery bags alongside news stories about design students who make skateboard decks from discarded plastic.

"To use recycled plastics, they have to consider two things: Is there an impact on the appearance, and what is the implication for cost?" Kosior said. "The brand owner always wants the product to look identical on the shelf."

Over the past few years, oil production has surged, causing a glut of global crude oil . This has kept the price down, and since plastics are made from oil, the cost of making new plastic has stayed low. When oil is pricier, using recycled plastics can be cheaper than making "virgin" plastic from scratch but at the moment, the opposite is true. Our recycling process also isn't perfect, and can sometimes lead to slightly lower quality plastics or variations in color or feel—these may be barely noticeable to the consumer, but to a brand, that's more variation than they want to gamble with.

"It's a very interesting situation," said Edward Kosior, a chemical engineer who started an independent consultancy on plastic recycling called Nextek. "The context for all of this is the price of oil."

There are also technological barriers to manufacturing more recycled plastic goods, Garcia told me. Recycling is a complicated process . Plastics have to be cleaned, sorted, and melted to be reshaped and reused. But most products are made of multiple kinds of plastic, each of which has to be sorted from the others before that can happen, and some—like PVC—can't be recycled at all.

The economic benefits for a manufacturer are also sometimes difficult to pin down, said Jeannette Garcia, a polymer chemist at IBM Research. Garcia said that efficiency, oil savings and the reduction in CO2 emissions that come from using recycled plastics are "invisible" to many manufacturers, while financial costs are obvious.

Garcia cited a number of examples, such as chemical recycling , where the plastic is exposed to a catalyst at a very high temperature, causing the underlying compounds to break down. It's how scientists have been able to make fuel out of old water bottles. Garcia said this technique still requires a lot of energy, and is very expensive, but she believes scientists will eventually figure out how to use a similar process at a much lower temperature.

Garcia said researchers are now looking for new and more efficient ways to make, and break down, plastics. "Since we make plastics chemically, the way we treat them at end of life is also probably going to be chemical," she said.

New techniques for making plastic could also make them easier to recycle, she said, pointing to a technique she co-developed to produce thermoset plastics—a polymer that actually gets stronger when you heat it up—that can be broken down and recycled.

There are cultural barriers to overcome as well.

"Most consumers wouldn't have a clue which plastics they can or can't recycle," said Nathalie Jerming-Havill, the senior creative strategist at Studio INTO, a design consultancy in London. Beyond that, there's a lack of pressure from buyers. "If the consumers don't want it, why should [the companies] care?"

Studio INTO supports a sustainable design challenge project every year for senior students at Central Saint Martins, a nearby arts college. This year, they challenged students to develop products that found new uses for plastics, which varied from plastic-free tampons to a take-away sushi containers made out of a soy sauce gel. Jerming-Havill told me the next generation of designers and engineers is eager to solve these problems, but big companies aren't as keen to adapt.

Even with green choices being "trendy," it's not always enough: Kosior estimated 25 percent of plastic products contain some small amount of recycled material, but it's not advertised because consumers believe recycled stuff ought to cost less. Garcia told me only 8.8 percent of plastic in the US is actually recycled, the rest ending up in landfills and the ocean. People still aren't willing to pay more, in dollars or effort, to save the planet.

Each of the experts I spoke to was surprisingly optimistic. As consumers become more aware, companies will start looking for better ways to incorporate recycled materials, and scientists are leading the charge.

"People are really chomping at the bit to be able to figure out how to address this issue and make a truly circular economy," Garcia said. "I am optimistic that we're heading in the right direction."