> 1995-2000 Microsoft's user interfaces were quite tasteful

Only because they copied NeXTSTEP. Those 3D beveled controls originated in NeXTSTSP. In Windows, ctl3d.dll added raised and sunken 3D-looking buttons, beveled text boxes, group boxes with depth, a light-source illusion using highlight and shadow, all copied from NeXTSTEP.