That's not the first time I've heard that Mainland China has better food (taste-wise and variety wise). Though I've heard there are a lot more foreign options.

As for convenience, Mainland China beats most countries I'd say. I wouldn't be surprised if it beat the world for convenience. I just returned home a month ago but during the end of my time there I was taking advantage of Meituan/Taobao. Getting your groceries delivered is a beaut!! Same goes for the public bike sharing system and payment systems.

The garbage can thing is exactly the same as Japan. They keep it spotlessly clean though. You're right there are a lot of garbage cans in Mainland China but unfortunately some people neglect to use them.