So far nothing perfect has ever been found by humans in this Universe and from my understanding of physics if it did exist all molecules in our universe would be equally distributed thus we wouldn't exist. It's all variables and compromises in any human endeavor these perfect loudspeakers could never exist since perfection itself doesn't exist. As far as rejecting lower eff that's more of a taste and experience or bias issue hi- eff low- eff most can have a good system built around them if you embrace strengths and mitigate known issues. If one wants dynamics, large image size, great transient response, and the ability to run off lower power but can accept a bit of size, different appearance from audiophile standards and can handle the limited market options or you can DIY, Hi Eff would be the logical choice. If you want what almost all audiophiles use and approve of, like to have many easy-to-source options, enjoy large power or need a small speaker. Low-Eff may be the best choice for you. There are still loudspeakers that are neither low or high eff those also may be worth checking out if you feel you want a bit of both worlds.
We should reject hard-to-drive speakers more often
Sorry I know this is a bit of a rant, but come on people!!
Too many audiophiles find speakers which are hard to drive and... stick with them!
We need to reject hard-to-drive speakers as being Hi-Fi. Too many of us want our speakers to be as demanding as we are with a glass of wine. "Oh, this speaker sounds great with any amplifier, but this one needs amps that weigh more than my car, so these speakers MUST sound better..."
Speakers which may be discerning of amplifier current delivery are not necessarily any good at all at playing actual music.
That is all.