Because in their minds, the market will eventually dry up, and... they're not wrong. There's not many folks looking for a new Apple ][ these days. And since continuing business means needing to access ever-increasing amounts of capital to create the next thing to sell, they have to make the number bigger. Otherwise the business goes under.
Honestly, their hangup on that last point is perplexing, because as long as the big shareholders get a decent cut in a long enough horizon to hedge or exit positions, they don't care if the company goes kaput. See GE. Jack Welch basically parted out the company like a corporate raider. It was obvious what would happen: at some point, there would be nothing left to sell and the company could not continue as an independent going concern. But you could mark the sale of a division as income for the quarterly report, and it made them meet projections, so it was seen as visionary.
Honestly, their hangup on that last point is perplexing, because as long as the big shareholders get a decent cut in a long enough horizon to hedge or exit positions, they don't care if the company goes kaput. See GE. Jack Welch basically parted out the company like a corporate raider. It was obvious what would happen: at some point, there would be nothing left to sell and the company could not continue as an independent going concern. But you could mark the sale of a division as income for the quarterly report, and it made them meet projections, so it was seen as visionary.