Which is my point, they don't really provide significant savings over a hybrid if you drive a lot. And if you don't drive much then owning just about anything works fine.
Sure, for people that have a short commute but take long weekend trips it's a net gain. However, I suspect that's a relatively small segment.
The modern Volt has a 50 mile range. That fits the vast majority of people's commutes, and if they can charge on both ends means a very large gas savings. But the biggest is convenience: no trips to the gas station, no oil changes, no brakes.
It's super odd to me why there are so many non-plug-in hybrids made. You already paid for most of what you need as far as complexity, but you don't go all the way and just about eliminate gasoline usage.
Scandinavia and the Netherlands have the added advantage over 'most of the developed world' of having a lot of bicylce paths, NL being as flat as a pancake helps even more (though it can be very windy here).
Age, terrain, weather (temp, wind, precipitation), physical condition of the rider, traffic safety and so on are all contributing factors in whether or not you should take the bike or rather not. But under normal conditions in a place where cycling is safe and the weather is ok'ish 5 miles is biking distance.