Never, I don't think any of them will, which is why I will never buy one. I'm just not willing to pay $150 for a special controller (read: controller that can only be used for racing games).
I don't think you'll see any drastic price drops anytime soon. Seeing that it's only gone down about a $100 in the past 4-5 years, within 2 versions - I'm not sure we'll see anything big. It's just one of those things that don't lose much value.
It might, it might not, it's hard to tell the future. Seeing it as it's the only wheel Logitech makes (if they still do?), I wouldn't really expect it either. If they can make a profit, they will.
I still use my DFP, so the price works out to about $20 per year. That's less than 1/180 of the cost of going to see a movie everyday, so I think it's justifiable to spend that much, even with the price of games and console figured in.
It might, it might not, it's hard to tell the future. Seeing it as it's the only wheel Logitech makes (if they still do?), I wouldn't really expect it either. If they can make a profit, they will.
G27 is still on the website, and I still see DFGT's in stores although they are NOT on the site anymore... did they finally discontinue it? That'd be a shame, and a mistake IMO.
The G27 is still very much in production, Logitech just update the packaging and the code wheel. It is also in stock on their website. What may not be in production anymore is the DFGT. It is no longer available on the Logitech site, which make sense since it is a Playstation official wheel. It could possibly be rereleased though without the PS license.