What is your definition of "tech"? A very large amount of the electronics products in the world are made in China (specifically in/around Szhenzen and the wider Guangdong province). Both consumer goods and industrial goods. From the cheapest stuff to the most advanced and everything in between. They provide the manufacturing for brands fron all over the world, including goods "from the west".
The amount of economy that depends entirely on this low-cost, high-quality manufacturing is insanely large - both directly in electronics goods but also as part of many other industries because you need electronics to build anything else.
By "tech" I'm sort of vaguely handwaving at Silicon Valley et al. I agree that China has built up a massive manufacturing industry that the west depends on, but I don't think that "being a significant cog in the machine," so to speak, buys as much influence or bargaining power as being the maker or owner of the machine. It's better to have the Apples and Googles of the world than it is to have the SG Micros or BYD Electronics.
American consumer and industrial electronics companies are increasingly unable to deliver products without the Chinese supply chain. How does that not give significant bargaining power? Also factor in that the Chinese manufacturers also manufacturers for everyone else in the world, so they don't have to sell that capacity to USA. And that the share of production capacity that companies from America use is trending down anyways. Mostly due to Asia, Middle East and South America are still growing a lot. Then Africa is following, delayed by some decades.
Of course owning the end customer is generally better. But moving production is not something to take lightly.
