the quality is generally equal, but there is more variety i suppose. what you describe sounds like extremely bad quality. if you can share the brand then maybe someone can give more insights.
producing bricks with a LEGO logo is a low bar. selling them is more difficult. you need to sell a lot of them to make it worth it. in order to sell them at scale on bricklink you would need to target a lot of stores. how would you do that without the storeowners knowing? a single store would not sell enough without being noticed.
I would disagree. Quality is a hit-and-miss. I have some cheap chinese manufactured bricks that are far off the lego quality, and some others which have on-par quality and better color consitency.
yes, but it depends on the brand. there are some brands that have reliably good quality, and some that don't. i have been buying various brands in china for 10 years now and the quality was always decent or good.
producing bricks with a LEGO logo is a low bar. selling them is more difficult. you need to sell a lot of them to make it worth it. in order to sell them at scale on bricklink you would need to target a lot of stores. how would you do that without the storeowners knowing? a single store would not sell enough without being noticed.