Time alignment has nothing to do with instruments placement in an orchestra, that will (or sould) show up in the recording of said orchestra.
Remember, we are reproducing the recording of the orchestra and that recording includes cues as to where the sound of each instrument originated at the time of the recording.
Also, the speed of sound doesn’t change with frequency --
As mentioned above, time alignment in speakers has to do with the sounds coming out of different drive units. Take a guitar for example and a two-way speaker. Assuming that some of the notes of that guitar are reproduced by the tweeter and some by the woofer, you realise that a delay in the sound emanating from the woofer will sound odd --
As mentioned above, Wilson (and others) tries to minimise delays by aligning the drive units vertically - for example, the back of a tweeter with the back of a woofer, meaning the woofer cone will seem to be well in front of the tweeter.
The rest of the delay compansation has to be done in the xover -- a very difficult task and AFAIK very few speaker manufacturers attempt it.