It is not widely known that you can have both clean abstractions with simple implementations.
At the Viewpoint Research Institute[1] (co-founded by Alan Kay), they are trying to have their cake, give it to everyone, and eat it too[2]. They already have some successes, with for instance a set of several programming languages that can implement itself, from bare-bones X86 to sky-high abstraction, in less than 1500 lines; a TCP stack that takes 200 more lines (a 50 fold reduction compared to a typical C implementation); and more.
Efficiency wasn't even the priority. But as it turned out, many optimizations were either very generic (across several languages), or plain unnecessary (some things are faster than anticipated, to the point of being good enough).
[1]: http://vpri.org/