Yes! That's why you should be very very careful who you give your data because you are exactly one acquisition away from the same effect as a breach. Fortunately the GDPR affords some protection here, if the data was collected for one purpose it can not suddenly be used for another.
As for never selling the company: there is one other option: you could give users the option to destroy their data just prior to the transfer. Of course no acquirer would be interested but that is another way of dealing with it.