Median household disposable income in Mexico is around $9800 [0]
Median household disposable income in China is around $5,000 [1]
In reality, in Prefectures like Guangzhou, Shanghai, Beijing, and Tianjin you are seeing median household disposable incomes that are comparable to Mexico [2], hence why high value manufacturing is returning to MX, because Chinese high value manufacturers can't compete within the US with MX when factoring shipping costs.
Within Asia, Chinese high value manufacturing is still competitive, but is returning to Thailand and Malaysia for the same reason (all those consumer electronics factories in Guangzhou were started and managed by Malaysian Chinese in the 80s)
[0] - https://www.inegi.org.mx/temas/ingresoshog/
[1] - http://www.stats.gov.cn/english/PressRelease/202201/t2022011...
[2] - http://www.stats.gov.cn/english/PressRelease/202202/t2022022...
Also, I've never heard of BYD or CATL til you mentioned em, but I don't follow the EV market (battery tech notwithstanding) nor do I really care, but it does show that there is still some work to be done in brand perception if a normie like me hasn't heard about it.
Mexico's population ~130M, China's 1.3 billion.
But it began losing manufacturing to China due to cost pressures in the aftermath of China's WTO assenscion [0][1]. Then the Great Financial Crisis happened as well and Mexico saw a lost decade in the 2010s.
It's unsurprising that we're seeing manufacturing leave China now that incomes have reached around $400/month for skilled manufacturing [2][3][4], a similar amount that caused similar manufacturing to leave Mexico for China in the 2000s.
Thailand, Malaysia, Brazil, Russia, and Turkey all had similar stories as well in the 2000s-early 2010s. Poland. Hungary, Czechia, Slovakia, Croatia, and Romania almost faced the same issue as well but were lucky to be within the EU and neighboring Germany so pricing remained competitive.
[0] - https://www.voanews.com/a/a-13-a-2003-11-12-33-mexico-s-6729...
[1] - http://international-economy.com/TIE_Sp03_Rosen.pdf
[2] - https://www.inegi.org.mx/temas/ingresoshog/
[3] - http://www.stats.gov.cn/english/PressRelease/202201/t2022011...
[4] - http://www.stats.gov.cn/english/PressRelease/202202/t2022022...