I was thinking more as an argument against freely-distributed products/services with a big negative downside for the user/consumer. We don't allow an electric

I was thinking more as an argument against freely-distributed products/services with a big negative downside for the user/consumer. We don't allow an electric company to offer a "premium service tier" with a line installed to your house and a "free tier" for people who want to climb a pole and attach their own cable — even if there are a small number people could do this safely. Now this could lead some people not to be able to afford, say, paid-only email, but then there could be options for people who can't pay for email, like a government program or non-profit organizations, just like there is for people who can't afford their electric bills. A church or other community group could even provide email to their members if you don't want it to be a government program, for example.