not even dvd format is really replaced or outdated in the eyes of the majority of movie buyers.
i think maybe there will be a new format some day. but that does not mean people will stop buying blu rays instantly.
DVD replaced VHS completely and VHS was phased out fairly quickly. The step up in quality between those formats was quite large. That cannot happen with blu ray, as the step up in many consumers eyes is basically not worth the price. Only those already into Home Cinema and HD formats as well as PS3 owners made the jump initially. Thanks to studio/marketing they were able to replace VHS completely. Although blu ray is now outselling "according to HMV/Amazon" DVD by some margin it still hasn't got enough of the market share for dvd to be phased out yet.
Yes DVD is still around, but it's price range on a consumer level "IE Proper retail/Online stores" has all but vanished. Brand new chart DVD's are less than half the price they were 2 years ago, and the collectors side has vanished as the studio's are now concentrating mainly on only providing blu-ray with extra footage etc. Criterion DVD once the grail of the format used to go for $000's now they are bargain bin prices even on eBay.
Chipvideo is 100% right, you can provide links for both sides of the discussion showing seriously ridiculously high prices and amazingly low prices and that proves very little to how a market operates. The "Collectables" market is very much a grey area when it comes to an actual market value as many here have already said it boils down to "How badly do you want it" because of that there always be those prepared to pay silly money for items that have a personal worth to them rather than actual market/monetary worth. Looking across the prices over the last couple of months it wouldn't take a detailed market analysis to see prices generally ARE going down. The early sought after ones will hold value because they were produced at a time when companies wanted to entice adopters to the format by offering above and beyond the normal. Now virtually every film is getting a steelbook somewhere on the planet and most of the time not in very small numbers which has resulted now in a decline across the board in prices. While some resellers might still be earning from this is more by luck and being in a good market area rather than this still being the way it was a year ago.
While even I myself have managed to get great buys I do browse eBay for a couple of hours each evening and overall the prices for "most" steels is slowly coming down and it has been doing so since the summer. There have been VERY low auctions and there have been some ridiculously high buy it nows but looking at the bulk in between those "which is how a market is assessed" the prices are falling due to the amount of releases now.
The buzz word for the idiots that run the studios is "steelbook" because they know it has a market and they will be able to charge a little more. What they no longer care about due to blu ray being far more popular these days is offering something above and beyond which is left to small companies like Blufans etc. The fact the studios have now discovered this is the death sentence of anything highly collectable as they will flood the market with product till it implodes in on itself. Then the studios will having taken all your money move on to the next collectable and eventually ruin it to!
On a visual medium side I started collecting Laserdiscs in the very early 90's and watched as it went from humble beginnings, through a few boom years with amazing artwork, THX mastering and the birth of DTS/Dolby Digital, through to it's eventual over saturated mass produced death at the hands of DVD. Granted it was a far more niche market only really doing well with early diehard home cinema fans and movie buffs in the US and Japan, everywhere else it was a very small market share product but blu ray hasn't been vastly different. It didn't take off well having to do battle with another format which for many consumers is off putting as they don't know which one will win. It took a long time for it to get going and then some time again before it's sales started beating DVD. Even then the only reason it's sales have done so well is because physical formats are dying slowly with sales dropping every year. Blu ray is new, better and HD fans moved to it, but it still isn't viewed by many as dvd's replacement. On that reason it hasn't been the success the powers that be wanted it to be, so they had to initially offer deluxe packaging. Now that they see this worked and has grown into a small market they will exploit that just as they did with Laserdisc, which will eventually cause it's death as a sought after collectable.
It seems to be in it's second wind right now. There's not really much coming out that beats the quality of those early releases thought wise except by dedicated companies and there is starting to be an abundance of releases for virtually everything by the studios with very little or miss guided "Lionsgate comps" thought put into them. While we maybe a couple of years off this market is now at the top of the slope and there's a studio exec on their way to push it over and downwards which for people like me is fab as I refuse to pay high prices for what is essentially a nice box, but not so good for those earning a living from it.