Each different factory has their own standards, and operate independently. The corporation has their own profit goals for that plant. And they may decide the market segment that factory serves to help avoid inter-corporate competition. But yet serve the broader market needs. Entry level, Mid-range, Top of the line, Luxury, etc.
And the corporation can sign volume contracts to buy high volumes of appliances, tires, frames, etc. And get lower pricing as a result. This helps the individual plants keep fixed costs under control and profit within corporate standards.
Most conglomerates do little to interfere with details of running a successful business that they buy. Now if they buy a failing business that is a completely different thing.
Bottom line...One brand can be just great. While another one can be problematic. It just depends on how the individual factory is run.