I don't need to guess. I know from having been to China and having talked to people.
It's mostly a combination of 3 things:
- Tons of infrastructure. If you decide to start manufacturing some random thing you can easily get all the stuff you need to get started.
- Regulations are generally very favorable to small startups and businesses. This is partly why so much of the stuff on Temu is crap.
- A huge population. That's the main source of ultra cheap labor. Farmers in rural China can still make as little as $1.90 per day. All a factory owner needs to offer is more than that and they'll have a line of applicants.
It matters more in solids.
If you add some salt to sauces, you can just give it a few stirs to incorporate it.