Scada systems have a much slower turnaround and update rate that general computer systems.
There are still systems in use that were designed in the 70's, someone i know who fixed minicomputer systems before he retired a year or two ago, said that they were still fixing PDP8's, mostly on production lines.
Its not surprising that ActiveX is still being used. It was probably written it that small window of about a year and a half when most people thaught it was a good idea. The people who design and maintain industrial machenery tend to adopt the attitude "If it aint broke, dont fix it".