A few things to keep in mind:
Though the Baron is still being produced this isn't a very important factor in determining support costs. If Beech ceased production tomorrow there would still be several thousand models actively flying, therefore, Beech would continue to make a killing making replacement parts. As would all of the third party vendors who make the widgets & gadgets that make the "clock tick."
Here's the big picture according to me:
When an organization sets out to purchase an aircraft, at least those who do it in a wise manner, they usually lay out a list of what is important vs. what isn't. A sort of broad based "what we need, what we want, what is important, and what we could care less about" list. This will usually lead to determining the mission capability that they are willing to pay for and a cost vs. benefit analysis.
Every organization could benefit from the use of a brand new Gulfstream V but only a select few can justify the costs associated with the benefit of such a mission capable machine. Conversely, Coca-Cola or 3M (both operate the V) aren't going to waste their time buying a used Baron to handle trips shorter than 200 miles involving fewer than 4 passengers. This isn't a cost consideration as much as it is a convenience and efficiency issue for them because of the size of their operation.
If a company defines their need as a way to transport 4 people on a trip that averages 200-350 miles with all-weather capability being a "want", then something like a Baron would be a good choice. If, however, they determine a need to be able to tackle about any flying condition conceivable (terrain, icing, T-storms, etc) because of a pressing issue then they are probably going to need to step up to a turbine aircraft. Should they determine that a typical mission includes 500+ miles and up to 6 passengers with the ability to return the same day then a light jet or higher end turbo-prop may be justified. Lastly, if the owner of a growing business can tough out a Baron for 5 hours in a day and the flying doesn't involve crossing the continental divide then he/she can accomplish a lot on a smaller budget than those who want/need a beefier airplane.
The same set of rules play out for comparing individual models within the same capability and price range. Out of ten people with the same set of needs a few are going to go with a twin Cessna a few with the Baron, and one or two will go for something that the others didn't think of. When things get this specific you would be amazed at what becomes important (looks, availability, urban legends, etc...)
Having flown about everything you mentioned I'd probably end up in a late model 421 if I intended to take it across the country now and then. If I just want to hop around the state and not worry about finicky engines and pressuriztion maintenance than you would most likely find me in the Baron, the newer the better.
I hope I didn't bore you or distract you from the original question, maybe I had too much coffee a while go;-)
