Overheard in the boardroom:- "get it sold, then move on; we'll worry about 'service' later (if at all)"!
Although the "big" manufacturers all have well-established service departments (many being international in reach), the Big Shots at the top probably don't worry too much about the revenue to be generated by a few Service Contracts, spare parts and what-have-you. Although they may well be mistaken in that view, their main focus is always going to be the Big Bucks made by selling capital equipment (or lots of smaller new equipment).
Meanwhile, the "smaller" manufacturers probably see Service as a cost (or overhead), rather than a profit centre (potentially, at least).
Some companies - those of the "one product" variety - try to get away without the Service overhead at all (that is, don't have their own service engineers). A lot of these companies such as these are actually just
importers anyway - and often don't really have much of a clue (or even care overly much) about the
technicalities of the stuff they are flogging.
Some may rely solely on the warranty afforded by the OEM ... which may (or may not) be next to worthless as far as the end user (
aka the Customer) is concerned.
But that's OK, as it opens the door* for my own favourite:- the third-party service provider; folk for whom
service is the primary concern of their business (rather than a begrudged after-thought).
I have never worked for a manufacturer myself, but instead have preferred to work for Service, as well as O&M, companies ... both of which tend to be managed by engineers rather than salesmen (or even worse, bean counters).
That's not to say that engineers can not be
entrepreneurs, far from it, in fact. But in my experience, service companies rarely make Big Bucks (and almost never the "quick kill") and it's a game that has be considered over the Long Haul. That is, after thirty years or so of carefully plodding on you might find that you've made a few quid after all!

*
Or should that be "the window of opportunity"?