BMW sales do not seem shrinking to me: They boast 35 consecutive quarters of growth [1] and sold more cars year over year, at least in 2014-2017 [2], don't know about 2018, as it's not yet in the statistics.

[1] https://www.press.bmwgroup.com/global/article/detail/T028306...

[2] https://www.statista.com/statistics/264342/global-sales-volu...