Not the beer, but the company. Even places like Guiness come out with new stuff like Baltimore Blonde to increase their line up and appeal to a bigger market for better scale.

the same reason as any market needs to innovate : consumer trends and goals shift with the times.

Let's take the most run-of-the-mill common bolt in the world as a product example : the 200 year old company that has changed to sell that run-of-the-mill bolt online w/ fast delivery and with a companion app has innovated without a product change.

innovation doesn't imply a product change, it implies that a company is necessarily flexible to meet the shifting demands of consumers. This can be done in other ways than shoving newer and shinier products out the door.

It doesn’t have to necessarily, however, it does have to in inverse proportion to how much their product appeals to the market presently. If your popularity and sales, for instance, take a 50% hit, you’d better introduce some new product lines. That doesn’t have to mean abandoning your original recipe product.