Vizio disrupted the HDTV market back in 2002 with its strategy of outsourcing manufacturing to Foxconn, which allowed them to make quality products for reasonable prices.
According to a Zeebox article, Vizio outsources its TV manufacturing to eight different companies: AmTran Technology, Foxconn, BOE, Innolux, KIE, Tonly, TPV, and Zylux.
As a result of more inexpensive outsourced labor, however, Vizio has also come under fire for not having any official policies on worker treatment for its suppliers to follow.
Regarding quality, reviews for their 2019-2021 products have been more positive, with CNET highlighting several Vizio models as being fantastic budget TVs.