Re:Only makes things worse (Score 1)

The telcos used lead-acid batteries as a filter for the line in addition to back-up. If you have an analog signal riding on top of a constant current source like with POTS, you need an *extremely* stable DC level or else people will hear buzzing. For a very long time (and maybe even now), the cheapest and easiest way to do this was to run the whole system off batteries.

So I think this could be classified as "good business sense", though for reasons completely unrelated to reliability.