Not necessarily, acquisitions aren't all one kind of thing. The motive for the acquisition greatly impacts the outcome. If it's a technology/IP acquisition or a personnel acquisition, then yes, generally expect that the original company's products will vanish. Why? Because the products were never part of the recognized value of the purchase.

If it's a business process acquisition, then it's more likely the product(s) will remain. This depends more on the motives and details of the acquiring vs. the acquired companies. If the acquisition leaves the acquired as a wholly-owned subsidiary, then one can expect the products to remain.