There's no cut-and-dried solution to your question!
Keeping it topical with today morning's post... people had all but written off COBOL, and along came Y2K and they were all back to "flavour of the year"
:-). On a similar trajectory I suspect there would be Delphi, and similar applications that might need maintenance at an appropriate time. One never knows which profession becomes the "blue-eyed-child" of the future. Many of my friends in Mechanical Engg., were laughed out of the career counsellor's office because IT's the "cool jive, maan"... Then IT stagnated, but the traditional civil and mechanical ones have boomed with infrastructure, transit rail projects and similar ones around, not to mention quick trips to the Gulf to maintain those pesky oil-refineries.
On another note, namely "appropriate jobs" is also like a lottery IMO! For, example, one of my ex-boss was a complete nincompoop and our team would always feel that I would be a better replacement for him. This collective feeling would spill over in his presence and he gave me a lot of hell as a consequence, even though I was content to be "loser" and tide my time away for ERE. His only qualification for the top-job was that we was warming the chair in the company, while I was out getting my PhD! So, in one sense he was "best of crop" at that time and so became my boss by default when I rejoined the workforce. There's no way one can foresee this kind of thing either....
The real way in which I see this panning out is like this:
Even though I was just .25 x ER before walking out, I had a great sense of confidence and a "I don't really need this job as a sole means to fund me" attitude which was beginning to get noticed (and became even more threatening for my ex-boss)! Once you are ERE, any job you'd take would just be topping your ERE fund or some spare change for a rainy day, so to speak. In my own case, some of the ERE habits are clearly a one-way street, and your expenses wouldn't really shoot up later!
Lastly, employers take "guts" over "talent" any day (forgive my sexist sentence, but you get the sense, I hope), because frankly speaking 80-90% of the jobs out there are so 'cookie-cutter', I could train our kitten to do a decent job in it if it came to that! :-)
People, no offence to anyone meant there!
EDIT: Altered balls to guts.