[deepnotderp]

Okay, first of all, we are no where near Landauer's Limit right now, and will likely never reach that point because we'll run into thermal noise "danger zones" far before then.

Second of all, there are plenty of (and probably the primary ) forms of non-quantum reversible logic.

In the slightly less exotic category there is also adiabatic computing which can actually be done in standard CMOS in most flavors.