The back-tick issue is interesting and I really don't care as long as it is consistent in all vm's but why not turn on language extensions/features to tell the

The back-tick issue is interesting and I really don't care as long as it is consistent in all vm's but why not turn on language extensions/features to tell the runtime how to interpret the code? We already use "use strict;" why no add "use ES6;" (please don't complain about my use of semicolons)