I agree with comments that the Omega, as with any car won't be worth anything more than any other car in a similar state of excellent condition. But I also have the thought that as with Allegros, TR7s etc, they had a period where people considered them just too ordinary and mass market to ever be collectible, and now they're suddenly wanted.
I'd like to think that one day there'll be a generation of chaps out there who are retired, after a great career in marketing/sales/repping, who with their disposable income/pensions, would like to add to their car collection their first 'proper' rep's car they had as a junior rep all them years ago. As I say, Omegas were literally the cheapest rear-drive repmobile there was, and you could have had either a Vectra - or, the
same car (albeit without the leather, and many toys) as the guy that'd been in the job 5 more years than you. OK, it's not the stock standard 5-series, like the Manager had, but it got you the same amount of space, comfort and luxury as he had, for about a third less money.
Just look at the market for vintage games consoles - exploded because of 30/40somethings wanting to have another stab at their teens with their Atari/Spectrum/NES etc
I do wonder, though about parts. On the one hand they're getting impossible to get hold of and we're
dooomed. On the other hand, each generation moves things on, with regards to technology. To fabricate a PCB would seem impossible witchcraft to someone working in cutting-edge Codebreaking in WW2, but now it's relative childsplay to many. Just look at what the generation who grew up with programming and writing code on their Sinclairs/BBC Acorns have done - photorealistic gaming and CGI beyond belief. The next generation will/are growing up with handing in their reports on touchscreen tablets and making projects on 3D printers at school. 3D printing alone is possibly the most exciting technology since the means to press sheet metal was invented. And the possibilities could mean panels, headlamp adjusters, even crank sensors could be knocked up in some kid's bedroom for pence. I theorise, just for fun, and of course no-one knows.
Life's no fun without a challenge - and Omegas certainly are that.