Yes, it's consumerism, but it's also new and better technology. Personally I'm satisfied with VHS quality and I still tape films from time to time if I have the opportunity. But DVD was a huge improvement in sound and quality which i appreciate immensly (though the main factor for me was always the dubbing on VHS in Germany and the subtitle option on DVD ) HD and Blu-ray offer even better sound and image, something which i appreciate again. As to what format to choose. I don't see any reason to giver up DVD. For us cineastes, HD and Blu-ray are a welcome treat, but I really don#t appreciate our capitalist societies who have to immediately rush out and buy everything "new". I will start buying HD or Blu-ray when they will be as cheap as DVDs. If not, I won't be purchasing any. And I don't think you ever have to change formats or technology if you don't want to. There is an infinite amount of VHS and DVDs on the market which you can enjoy your whole life. Right now, I'm buying more LPs again, as I never was such a huge fan of the Compact Disc 

We are currently discussing this topic at the DVDBeaver mailinglist ad infinitum (I'm already a bit sick of it ), and the machinations of the big companies in this format war are really a sad example of our money loving prestige seeking society. 

I hope both formats will be compatible in some players in the future. And as I read somewhere else: there are probably already even better and more advanced technologies being developed this very moment