These days it seems 'fashionable' to offer long warranty periods. Gone are the days of offering 12 months warranty.
Turbos aren't the same as the usual consumer product, if your television stops working after only 9 months, you simply return it to the store and they will replace it free of charge, unless it has failed due to user abuse.
A turbo relies on a supply of 'clean' oil, air and exhaust gases to operate properly. Without such conditions the turbo will not perform correctly and will fail prematurely.
Prolonging service intervals severely affects how well the internal components perform, carbon build up narrows oilways within the engine and the turbo, insufficient lubrication and cooling amplifies this problem. This is commonly indicated by 'blueing' (heat discolouration) of the internal components.