And I continue to see examples every day....network devices (and any other equipment) plugged into battery backup units are more reliable and the equipment lasts longer. Less "rebooting" of equipment needed, less "another dead Linksys router" replacing of equipment.
This is comparing apples to buffalo wings to napkins. A unit that has problems due to software failures has no relationship to another that has hardware failures. Both symptoms must be discussed separately. Especially since a power strip protector is only for hardware protection whereas a UPS is only for software protection.
Furthermore, UPS here refers to a plug-in adjacent unit - not building wide or 3000 watt rack mounted UPS that is electrically different - that performs different functions - that contains other functions.
Brownouts are not hardware destructive. That was even an international design standard long before PCs existed. Ideal voltage for electronics is even when incandescent bulbs dim to 50% intensity. All such voltage variations (also called sags or brownouts) must be made irrelevant by what is inside electronics. AC voltages can vary as much as 85 to 265 volts. Internal voltages must vary as little as 2%. Where is the damage? Why must AC voltages be better regulated? They don't.
Battery backup units (discussed here) do not condition power. Especially not $45 - 65 dollar boxes. Most connect an appliance directly to AC mains when not in battery backup mode. Nothing exists to condition power other than superior filters and regulators that must already be inside all electronics.
UPS output 'diritest' power when in battery backup mode. Why? All electronics are so robust to - as the example demonstrated - to make irrelevant 200 volt waves with up to 270 volt spikes. Any electronics harmed by this were defective when purchased.
An AC utility also demonstrates 'dirty' UPS power. That UPS switches from AC mains (on left) to battery (on right). Waveforms (figures 1&2) demonstrate 'dirtier' power is from a UPS battery:
http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-03.asp
We constantly repaired equipment to discover failure reasons. In one case, they a powered off computer would not power back on. Using observation, power cycling was blamed. Then I did the analysis. A pullup resistor had failed - probably during many months that computer had been left on. Damage probably occurred months earlier. Resistor's only function was to bootstrap power during power on. Damage from months previously was observed only during power cycling. They used observation - not facts. They blamed power cycling because observation was not tempered by facts and how electronics work.
Conclusion based only in observation is why junk science exists. One must know details - the reasons why - before making conclusions.
Another example. Why do clocks, dishwasher. GFCIs, smoke detectors, and other less robust devices such as dimmers switches not fail so more often? Those devices do not have UPS protection. Their internal protection is even less robust. One cannot 'cherry pick' observations. All examples must be considered if making any observations.
Some devices are at greatest risk when an actual problem is not addressed. Therefore best evidence comes from the dead body - an autopsy. If something (completely different and not yet discussed) does not exist, then modems may act as protectors for other building electronics. But again, to say more requires facts - not observations. Without facts and a discussion of everything (every item in a building and building wiring), then only junk science conclusions are possible.
Accurately noted is a high failure rate for home UPSes (ie 3-5 years for a battery). These are made as cheaply as possible. Even my car battery, used multiple times every day and in a much harsher environment, lasts seven years or longer. That APC UPS does not protect hardware. It does provide temporary and 'dirty' power during blackouts to protect unsaved data.
What hardware is protected? Which electronic part? Any protection from brownouts is unnecessary - a mythical fear.
Do you know about a safety lockout feature in some electronics? Power off (by disconnecting its power cord - not just a power off) clears this safety lockout feature. Observation would blame a brownout rather than that protection feature. Another example of why observation, not tempered by internal hardware facts, can result in junk science conclusions.
We have not yet discussed what is essential to protect all household and server hardware - and from what. Unfortunately that discuss required longer posts.