Earl has a good post about innovation and myths about it. He quotes Marco Rinesi:

But for all of its undeniable power, the printing press wasn’t the source of large fortunes for the engineers, investors, and businessmen involved in this industry. Profits were made, yes, sometimes significant ones, but nothing quite proportional to the influence of the technology. The bulk of the benefits came to the organizations that leveraged this technology for their own ends like modern states, which would have been logistically impossible without the printing press, or the myriad business that cannot be conceived without a superbly well-educated (for pre-modern standards) source of workers and consumers.

The same pattern can be seen in many other technical advances, specially those that impacted society the most. Contraceptives, telecommunications, refrigeration: they are often overlooked foundations of the contemporary world, each of them enormously disruptive, yet none of them, over the long term, a gold mine of extraordinary returns.