On envelope window standards: We’ve

On envelope window standards:
We've got standards all over the place, why don't we have standards for which side of the envelope the clear window goes on? Sometimes it's on the right, sometimes it's on the left. If it were always in the same place, companies (mine for instance) could order a whole slew of envelopes with windows all in the same place, with our return address pre-printed on it, even pre-stamped perhaps. And then the bills with their pre-printed address would line up perfectly in the windows. Instead of windows all willy-nilly all over the place.