Well, at least certain types of bulbs are... ;-)
Few people seem to know just how much brighter 110-120 volt driven bulbs are, than their 220-240 volt equivalents, a very noticeable difference.
Rounding off typical values,
a 100W American bulb gives out 1800 lumens, the European equivalent 1300 lumens.
Put another way,
a 75W US bulb (1100-1200 lumen) is closer to the European 100W bulb,
conversely, the 100W US bulb is close to a European 150W bulb (2000 lumen).
"Dimmest" of all are the Brits...
At least in theory, given 240 volt rated mains voltage and with imported bulbs rated 230 volt or 220-240 volt in lumen value, so as to also correspond to other European countries.
In return, the British bulbs should last slightly longer.
That is also why 100W US bulbs were commonly (pre-ban) only rated 750 hours,
compared to 1000 hours for EU 100W bulbs, and 1000 hours for 60W and other lesser wattages, regardless of origin.
image Ronald Hudson 123rf.com
Both energy and cost wise, "brightness wins" over lifespan trade-offs:
Look at the new fad of selling "legal long lasting incandescents" in the USA, as 130 volt bulbs, or as rough service bulbs, the latter also in the EU.
While they may only be a temporary workaround for those seeking to use incandescents
(imports and sales are monitored, at least in theory in the USA, given the current ban on oversight funding as covered in previous posts, see below), there is as mentioned an irony here: They use much more energy than equivalently bright banned incandescents!
This is easy to work out once you start taking a 100 watt long-lasting legal incandescent
and work out the energy usage of shorter lasting 75 watt legal incandescents
- bulb cheapness means that even using up 5, 10 or more bulbs for 1 long-lasting bulb,
the overall cost as well as energy use is much higher with the legal kind.
A worked example is covered in the http://ceolas.net/#li01inx section,
also in the post "US Regulation Absurdity: Dim 100W bulbs allowed, Bright 100W bulbs banned!"