You haven't flown or maintained aircraft; you're SSG, the banned impersonator. Everybody knows that.
Most certainly turbojet engines have oil lines, and oil return lines, and indeed turbojet engines have governors; many have multiple governors to include speed governors CSD governing functions, etc. Even multiple oil sources, pumps, systems, etc...and yes, turbojet engines do have oil leaks and run out of oil. Earlier this year I lost seven gallons of oil on one leg.
Your assertion that one should reject a turbopropeller out of hand because you claim to have had an oil problem as a passenger at one time is ridiculous. Particularly in this case as we're talking about the piaggio avanti...and you're posting regarding an airplane, in a thread about the airplane, with which you have zero experience. None.
Your claim that a turbojet engine isn't susceptible to icing indicates that you have zero experience with turbojet engines, and apparently have never experienced ice, or the need for anti-ice, in a turbojet engine. The fact is that given the same conditions, a PT6A installation is often superior, and far less susceptible to damage from ice ingestion...given that it acts as a natural inertial separator and PT6A installations also use inertial separation equipment in the form of ice vanes and exit doors. Ice is a much bigger threat to turbojet engines.
You might be unfamiliar with what happens when a turbojet engine sheds a blade...but it does happen, and surprise surprise...most turbojet engines have more of them to lose. Turbojet engines also have RPM limits...just like turboprop powerplants.
As for the Piaggio...it outperforms some turbojets, goes just as high, faster, and with much better fuel efficiency and a bigger cabin...and it's quiet inside. Furthermore, it's a popular choice where image to stockholders or investors is important; with the performance of a turbojet and the appearance of a more frugal turboprop, and the lower turboprop operating economy, it fits the bill.
Perhaps you'll get an add-on for your microsoft flight simulator...and you can try an Avanti out...and add it to the list of other aircraft you've "flown."
I've served as a mechanic and director of maintenance for turbojet and turboprop operations, and really don't think you have a clue what you're talking about with respect to systems or experience. Your previous postings under other names have done nothing to contribute to the various forums in which you impose, and your obvious lack of experience here, particularly with the Avanti, means that your input here does little more than dumb down the thread.