Oh very much so. That's why China is careful about starting a trade war with Apple. They want to get their own manufacturers up to speed to replace Apple, but they don't want to just kick Apple out of China in one stroke and penalize the Chinese businesses that depend upon Apple.
If it wasn't for that, Apple and their strong privacy approach would be Persona Non Grata, IM-uninformed-O.
Apple tries to be less public about them having HUUGE R&D and business units in China with lots of things being done here.
In 2016 they posted a tiny press release about them opening their "first" R&D centre in China in Shenzhen, and deliberately making an impression of it having no significant role.
In reality, it was their _third_ RnD centre in Shenzhen only. Besides their nominal "design centre" in Kerry plaza, they rent a whole building in Discovery park in Nanshan, and have own section in Foxconn campus. The rumor is that they also rent yet another office for their product/project management staff somewhere closer to Longhua.
But more than 50% of iPhone value is Chinese made.
Materials, labour, machine time, big part of ICs, batteries, passives, cabling, etc.
So, China actually double taxes own manufacturers aside from Apple itself.
The meme that "only $20" of iPhones value stays in China" is completely wrong. China makes tons of money from Apple.