In order to scale, in whatever business, work must be shared. But with infinite possible combinations, where should you draw the demarcations? Luckily ITIL describes the combinations that in general have been shown to work well. Don’t go away thinking that ITIL is the only way, or even the ‘best’ way to arrange affairs in IT. If you run an insular IT shop (increasingly unlikely these days) i.e. high staff retention, low requirement volatility etc. then possibly some non-ITIL combination will work better.
ITILExpert’s take: ITIL is not an invention. ITIL is a description. Rather like discovering a useful complex compound. The chemical formula is not an invention it is a description. Once you have the description you can replicate it – and thus it scales.