I'm going to describe an automotive technology for you, and you try to guess what I'm talking about.
This technology started out with the best of intentions. It was supposed to increase vehicle performance and fuel efficiency, but it proved too costly, undependable and unrefined to deliver on that promise. Sure, it worked in laboratory tests and under very specific real-world conditions, but the technology's potential for benefitting real-world, consumer-oriented vehicles appeared slim. While repeated attempts to improve the technology's effectiveness occurred within the R&D departments of various automakers and suppliers, it's widespread adoption on mainstream models seemed unlikely.
So, am I talking about hybrid drivetrains or fuel injection? Of course by now you know I'm talking about both.
I raise this issue in part because of Toyota's recent announcement o make all their vehicle's hybrids by 2020. While lauded by many, I find the time-frame rather unambitious. In my opinion, hybrid technology is exactly like fuel injection. It started out clunky, expensive and somewhat undependable but is quickly improving in capability, refinement and cost structure. Fifty years ago fuel injection was only on the most expensive and/or highest performance vehicles, it offered questionable advantages over carburetion, and it required a heavy and convoluted system of parts to operate. Now you can't buy a car without it because the technology just makes too much sense in terms of performance, fuel efficiency and emissions reduction.
Wait...I lost my train of thought. Was I just talking about fuel injection or hybrid drivetrains?
Anyway, there will come a day when hybrid technology is a ubiquitous drivetrain component serving to increase performance and/or fuel efficiency. It will be small, modular (meaning easy to use on mulitple models within a company's product offering) and its cost will be a required (and negligible) part of producing the entire vehicle. Heck, there will even be aftermarket conversions to put it on cars that never had it originally.
And, personally, I think that day is earlier than January 1, 2020. With the pace of technological breakthroughs in today's world it should not take as long for hybrid drivetrains to become commonplace as it did for fuel injection.