So while this is a problem, I doubt it's really all that related to landfills vs. recycling. Some of that exported waste was
supposed to be recycled, almost certainly. It's likely that exporting for the purpose of recycling runs essentially the same risks, not to mention that you have to consider not just incompetence but outright malice too: why wouldn't a waste-processor not take stuff for recycling with the intent of never recycling in the first place? By the time the sender catches on, just let some intermediary go bankrupt, rinse, repeat.
Waste export problems have little to do with landfills vs. recycling. If anything, recycling has additional risks, because recycling is tricky and potentially labor intensive, making exports alluring, and because it has the veneer of cleanliness without good means to audit that.
However, if the argument is that exporting waste is generally speaking a bad idea, that obviously holds merit. International agreements, standards & cooperation obviously weren't robust&benign enough to ensure that works in the past, and all but the smallest of countries should be able to figure this stuff out themselves.