What do you base that on? Blu-ray adoption is exceding the rate of DVD adoption in the same period since its introduction in 1997.
As you say, you're not in the US, but everytime you go into Best Buy lately the BR section is growing larger. The retailers are working to create that ecosystem. Studios are putting exclusive features on the BD versions of things, even though, as you say, they continue to put out DVDs.
I suppose that's down to the crowd you know. I'm probably biased knowing so many film people, but even my Mom, who still uses VHS on a semi-regular basis saw BD in the Costco and started talking about getting one.
1 and 4 - the BD player would replace the DVD player, same # of inputs you'd need now. and how many people actually have an

tv? Outside of this forum I mean. I've never seen one. I know more people that still have laserdisc players than have

tvs.
2 - see my point above
3 - The discs are more expensive now, but the studios are starting to come down. Warner Brothers has started reducing prices for catalog titles to $11 for retailers for example, which would lead to around $15 in store - same as an average catalog DVD. If you shop online you can find lower prices for discs generally as well. Entry level players are available here in the states for $300, at Wal-Mart and Costco etc. BR read only drives are available for $150 or less if you have your pc connected to your TV.