Roll your own. I do. There's no hard and fast rule about how to vape. Check out the tootle puffer's thread; you'll find lots of people perfectly happy under 20watts and just a couple ml per day. You can still also find and use high-ohm, low-watt tanks and coils therefor. Some of the very best, and earliest, flavor tanks-- Svoe-Maesto Kayfuns, Erlkonigin, etc-- were intended for this regime, although they are for coil builders.
The "obsolete" question is interesting: you meant "is economy becoming obsolete", of course. And, as I have said, it is not. But coils now... maybe. Yes, to be sure, some means of heating the juice to vapor temperature will always be required, and these will probably always be called "coils" as the electrical symbol for such a part (an inductance) is a coil shaped spiral. Already we see the ceramic coils making inroads to the coil-and-wick type. An improvement in design would not surprise me.
The market sells what people want to buy. I think-- personal opinion only, no data-- it probably has more to do with a preference for direct lung hits rather than MTL; and thus the high watt, high juice, low nic combo is merely an effective tool. It just works better in that regime is all.
Finally, another viable option is to DIY your juice. I do, in addition to building my own coils, and make it exactly how I want it for a nickel or so per ml. And then don't worry about how much of it I vape.