In the software business, this is a license with a limited term. It will never happen with ebooks, at least, not in a way that's commercially successful. Those who want DRM, of any kind, will simply never do it in a way that isn't obviously inferior for the consumer. In other words, there's no point to a system where you can increase your use period for an additional payment, to be able to load it out, because it will cost exactly the same as the person you're loaning it to simply buying it in the first place. And there's no possible way it will ever happen in the real world in a way that costs less than the one-time payment, indefinite use arrangement we have now (theoretially, anyway, some DRM content has already been lost through companies closing up). Charging you more for the same thing is the whole point of DRM, after all.
And regardless of how true the above is or isn't, it's the public perception of DRM, and so long as it is, there will be publishers willing to cater to the market by not using DRM. And those publishers will continue to thrive.
For an example of how an idea like yours can fail, and spectactularly so, go look up the original DIVX (not the codec used today, the DVD-like discs).