I don't think bit coin price is dropping for the reasons given.
If I were to buy an item using bitcoin, I would replace the bitcoin by buying more using fiat. i.e. I buy a computer for 2BTC, I would subsequently re-stock my BTC by buying 2BTC on the exchanges. This is basically price-neutral.

There is a much better explanation of why the price is dropping;
East European miners had effectively cornered the production of new BTC and were holding bitcoin back to squeeze the market and artificially raise the price. (Like deBeers did in South Africa with diamonds in the 19th century). Recently, new Chinese mining farms have started up big time, and the monopoly is broken (for the time being), with miners selling immediately in order to cover their costs. As the price drops further, miners are further encouraged to sell their newly minted BTC ASAP. What we are witnessing are the consequences of one mining cartel snatching control from another - a temporary state of affairs where true free-market forces can determine BTC price.

The problem is that the basic BTC economy is flawed - centralized ASIC mining is not working.