Cybill, of 250 typewriters that I have laid hands on 79% are pica and 21% are elite. Perhaps there is a manageable way to get those figures from the Typewriter Database, a 100 times larger sample..... Ted?.... I agree with your preference, though I wouldn't say pica looks unserious but that elite looks more elegant. That's just personal opinion, though.

As for why pica is so much more common, that will remain in the realm of opinion pending a lot more research. "Students wanted to fill up a page faster. Businesses wanted to maximize use of paper. Academics wanted ? Government wanted ? Newspapers wanted what, clarity?" Etc. And which markets were bigger?

Decal preservation? When the whole machine is clean, put a wax over everything. But be aware that "polish" is by definition abrasive, however slightly. And "cleaning" might work chemically as well as abrasively. Test, perhaps on some other less precious appliance of similar age. A pure wax should be safe enough. All that said, though, I have not had any trouble with the commonly available waxes and the results are great. Sometimes I see the paint tinting the polishing cloth and back off on the pressure; using a different wax would be better. If your paint or decals are flaking already, stabilize that before rubbing.