Do you consider these guys artists? Why are they not as admired as they should be?

The architect is the artist, these guys are following that 'artist's' vision, though that is not to say they don't have their own skillset. But they are not creating something out of the firmament of imagination. Someone has already done that for them.

You may as well say that I was an artist for building Lego models as a child by following the provided instructions.