[dagw]

could have been the Janes of IT industry

Which part of Janes? If you look at the whole portfolio of service offered by iHS, then they are much closer to something like Gartner Group than a publishing house. I imagine that the real money comes from writing custom reports and consulting work, with the high technical and very expensive years books coming in second. Their books and magazines are probably as much a marketing tool as a revenue stream.