Soundstage is determined by recording technique. For purist recordings the microphone setup is the determinate. For studio recordings soundstage info is created via electronic processors.
On the reproduction side it is not clear to me that audiophiles are interested in an accurate soundstage reproduction. Wider or deeper seems to be desired whether or not it is warranted. Dipoles, wide dispersion or rear firing tweeters and omnis all overlay additional soundstage info to what is already in the recording.
If your system can provide a reasonable facsimile of the real soundstage info present in a purist recording, it means your system a lot of other things really well.
On the reproduction side it is not clear to me that audiophiles are interested in an accurate soundstage reproduction. Wider or deeper seems to be desired whether or not it is warranted. Dipoles, wide dispersion or rear firing tweeters and omnis all overlay additional soundstage info to what is already in the recording.
If your system can provide a reasonable facsimile of the real soundstage info present in a purist recording, it means your system a lot of other things really well.