As Adrian van Hooydonk, the design chief of BMW, noted in an interview with BMWBLOG at CES, they (the company and its designers) knew that people would talk about the look of the new M3/M4 models due to the large grille. However, van Hooydonk explained, "we know that getting people talking is not necessarily bad."
Figures then showed that people were still getting the new M3/M4 at the time despite the big grille, and the same is probably happening with the 7 Series. Adrian van Hooydonk noted in the interview that it would be bad if "people would talk but not buy," which is a simple but honest simplification of the situation.
While some people (including some of us) were chatting online about BMW's new design strategy, the resulting look, and if the big grille is as bad in person as it looks in the photos (it's not – if you ask me), others were ordering these new BMWs.
It looks like not just the Chinese have ordered more BMWs with big grilles, but the new models are popping up on the streets in various other markets, and BMW is selling enough of them to know that it did attract the people who could afford the cars.
That last bit is the name of the game in the automotive industry – if an automaker intends to survive on the market, it needs to have people who can afford its cars to buy them. If they are selling enough of the models that make a profit for the automaker, the brand has a shot at existing further.
As for the grilles of future BMW models, well, you should brace yourselves, as Adrian van Hooydonk has confirmed that the brand has more grille changes on the way. Moreover, each vehicle will get a tailored grille, just like the M3 and M4 have large air intakes and the X7 has big and vertical grilles.
Moreover, BMW is not planning to change its design strategy after online and IRL criticism, as long as people keep buying their cars with their respective designs. In other words, if you do not like it, do not buy it, and if you can't afford it, maybe it is not for you to like it anyway.