Ill have to respectfully disagree with you on a couple points. The first being the pilot shortage.
I'm kinda confused about the expected progression here. What kind of work prepares you for EMS? Flying tours and the gulf doesn't. Flying Utility maybe has some parallels but as far as making weather decisions and flying at night with NVG's etc, not really. I would say the only thing that really prepares you for EMS is flying EMS. Not even the military seems to prepare you for the EMS industry (sure you may have loads of goggle time but how much time do you have flying as a solo PIC coming out of the military? Chances are that's a big fat zero). How do you get that experience without doing it? Also, EMS companies cannot keep staffed right now. And I don't think its a matter of not paying well enough (although I certainly wish they would pay better). I can't imagine that there is a load of qualified pilots out there waiting for an EMS operator to start paying what they are willing to work for. There just aren't enough "qualified" pilots anymore. There's a shortage. But that shortage is really only a matter of perspective. I think there are plenty of qualified pilots capable of doing EMS. And they aren't in the twilight of their careers either. Many of them just don't meet all of the requirements to get the jobs.
I went into EMS right out of tours with a little less than 3000 hours TT (1500 Turbine). EMS is pretty straight forward with good training and a company that doesn't push you to take flights. You have to have your head on straight and be thorough though. And in my short time as an EMS pilot, I can say that the best ones I know are coming from the tour industry, while a lot of the old, high time guys are lazy and barely competent. That's a personal anecdote, so mileage may vary, not available in all states, yada yada. I'm not trying to make a blanket statement. I have just found that there are lots of low to mid time pilots that definitely have what it takes to be safe and successful EMS pilots, and there is a need for them so companies cannot afford to be too picky about high time guys.
My biggest gripe with this industry is and always has been that every operator out there wants turn-key pilots who have experience doing that particular job. No one wants to have to invest in their people, and the ones that do make the pilot "earn it" by paying a **** wage while they get the experience they need to move on to a better paying operator. I am hoping the current trends in staffing force some change, but I would be willing to bet that the industry will simply shrink before that happens.
There is no pilot shortage. The endless sea of HEMS openings stems from the ridiculously low pay that is being offered. There are numerous pilots out there, myself included, who far exceed the minimum hiring standards but will not hop over because flying offshore, utility, and international work pays much more. But if AMC, Metro, MedTrans, etc start offering six figures and 14/14 schedule, you will see a wave of new talent coming in.
As to only the job itself being what prepares you for the job.... that is true to a certain extent. Any job will have certain unique aspects that you only learn from doing it. But there are also a lot of experiences that cross transfer. All the years one has spent dealing w/ mx issues, weather, emergencies, tough landing sites, training received from other 135 operators, etc prepare one for any job.
Wally hit the nail on the head. HEMS is a job you bring skill and experience to because youre not going to fly enough to build on that.
An exceptionally talented and professional pilot may have all the knowledge and skills they need at 3,000 hours to safely and efficiently carry out their career for the next 20 years. But that is the exception, not the norm. Most pilots in that experience range still have a lot they still need to figure out.