It's not easy to predict the valuation. For that, we would need to know how much business is done in bitcoin in the future. That's anyone's guess. Will it do $1 trillion or will it do more ?
The price isn't always going to rise at this rate. That's for certain. However, yes, there will probably be a long term rise until bitcoin finds it true usage, market cap, and as a result of this, it's value with steady deflation going forward.
While, I'm not sure what an economist's opinion on this is, the fact that you are encouraged to spend money because it's worth less in the future (inflationary fiat money) leaves a really bad taste in my mouth. Consumerism is a horrible disease and our planet is suffering from it every. single. day.
That brings me to bitcoin and it's deflationary nature. Well, you're still going to buy the stuff you want to buy. Then, you'll save more because you know it'll be worth more later. Why wouldn't you buy the things you always need ? (food, shelter, a few gadgets, etc.) Should I spend on a new iPad when I might be able to buy 6 months worth of food with that money a year or two later ?
You'll save as much as you can. You'll consume less junk. Isn't that a good thing ? Shouldn't we ask ourselves if we really need all the crap we keep buying ?
These are interesting questions that challenge the entire nature of mindless consumerism that most of us indulge in these days.
Also, if the only reason you spend your money is because it's going to be worth less tomorrow then you have bigger problems than bitcoin ;)
PS - I don't mean you personally, just stating some thoughts.