This depends on the line of business
"The evolution shouldn’t come as a surprise: the IT department is increasingly being seen as a profit rather than a cost centre with IT budgets commonly split between keeping the lights on and spend on innovation and revenue-generating projects."
It's a profit center only if your company is in the business of producing IT products or services. Otherwise it's a tool your company uses to perform their revenue generating functions. Yes, your IT systems can provide the latter organizations with a strategic advantage over your competition. In much the same way as an auto repair shop can excell by having higher quality and/or more capable tools.
Not the most important job in the IT process. Unless IT products/services are yor companies line of business. Its the process owning manager that makes the cost/benefit decisions on which tools to invest in and when to upgrade or replace those tools. These decisions need to be made with the support and operating costs of the legacy systems in mind. Which is where contributions from the operations (admins) as well as development (project) sides of the house need to be balanced against the user's cost/benefits.
All too often, IT systems are seen as projects that, when done, provide the project manager their little gold star, promotion and material for their CV. And once the system is delivered, its cost to the company go largely unnoticed. Untion the users or admins scream about it being crap. The smart company has someone in charge of the work process that can call for a new system to be built, even if the old one is stil functional. If that new system can produce a savings/benefit to justify the work done. On the other hand, the process owner might reccommend sticking with a clipboard and pencil on the shop floor if the shiny tablet/IT tool doesn't add value to the bottom line. The latter decision doesn't look as good on an IT manager's CV, but its a valid choice.