Short answer: if you want to execute a program (maybe with some instrumentation, for fuzzing purposes) it's much easier to adopt a dynamic approach (i.e., emulation or virtualization). With static binary translation you can get better performance, but there's a lot of other things you need to get 100% right and that with a dynamic approach are a given (e.g., the CFG).

There's much more space of improvement in the field of analyzing code (as opposed to running it), so we're investing our energies there.

Then we're strong believers in integrating dynamic and static information, for instance see PageBuster: https://rev.ng/blog/pagebuster

But other than that, static binary translation is a feature of rev.ng in maintenance mode.