I wonder if MS & the plc vendors are in some sort of pact (or maybe not), look at the facts.
Hardware:
PLC vendors insist on using weird comms so you have to spend £....
on converters, even some 232 ports are some weird plug.
Pc's are hard to get with 232 ports for your expensive 232 converter.
Then PCMCIA now defunct on most new pc's, dammmmm, just spent £800 on a DH card.
Vista, well I have £37,000 of plc, hmi & scada software most of which probably won't run on vista.
5-6 232 or pcmcia converters or special leads most of which will not work on latest hardware
To be honest only got another 9 years & I can retire, hope my 850mhz PIII with real serial ports, usb & PCMCIA lasts that long.
Come on PLC vendors all we need are USB for local connection & ethernet what could be simpler