I like your question, to understand what is at play, we need to think as to why speakers need to be measured in an anechoic or quasi anechoic environment.
The reason is that any other way and what you are measuring is the speaker and room, and even that measurement will change depending where the speakers are in the room and where the measurement is taking place. In other word the same speaker will measure differently.
With that in mind, yes, you can make an average speaker sound great with careful positioning, room treatment, some kind of electronic (EQ, Dirac, Audessey, etc...). Or make a great measuring speaker sound very average by ignoring careful positioning. Are better measuring speaker easier to position and EQ? Probably.
A great speaker can sound only as good as how it is set up, not surprisingly, all the people raving about their Genelec and Revel, in here, are also raving about REW measurement and DSP, proper room acoustic and speaker placement. You never hear, those speaker are so great they will sound great anywhere, the best you might get is that they will be easier to place and EQ.