The thing is BTCs are landing on the hands of these financial institutions. We have read public statements that they are hoarding hundreds of thousands of bitcoin. There's probably a small percentage that are held by retail investors from the BTC leaving the exchanges.
Good points on bringing up the "inventor didn't foresee" angle and using other examples. Appreciate that.
At the first glance, your concern is well warranted. Given the fact that there are many (and the number of them is consistently growing as time goes by) institutional investors, big holders, oligarchs hoarding their bitcoins without willing to ever spend them, what will happen to the bitcoin economy? Since we are still living under the old fiat system, it is hard to foretell if the bitcoin economy will ever become a reality. If that ever happens, the new bitcoin economy will be similar to that based on the gold standard. The problem of hoarding under the gold standard is thoroughly described and explained by Murray Rothbard in his famous work "What has government done to our money?". You can download it for free on mises.org, but here is the main idea:
The critic of monetary freedom is not so easily silenced, however. There is, in particular, the ancient bugbear of “hoarding.” The image is conjured up of the selfish old miser who, perhaps irrationally, perhaps from evil motives, hoards up gold unused in his cellar or treasure trove—thereby stopping the flow of circulation and trade, causing depressions and other problems. Is hoarding really a menace?
In the first place, what has simply happened is an increased demand for money on the part of the miser. As a result, prices of goods fall, and the purchasing power of the gold-ounce rises. There has been no loss to society, which simply carries on with a lower active supply of more “powerful” gold ounces.
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Economists err if they believe something is wrong when money is not in constant, active “circulation.” Money is only useful for exchange value, true, but it is not only useful at the actual moment of exchange. This truth has been often overlooked. Money is just as useful when lying “idle” in somebody's cash balance, even in a miser's “hoard.”11 For that money is being held now in wait for possible future exchange—it supplies to its owner, right now, the usefulness of permitting exchanges at any time—present or future—the owner might desire.
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Let us assume the supply remains constant, say at 3,000 tons. Now, suppose, for whatever reason—perhaps growing apprehension—people's demand for cash balances increases. Surely, it is a positive social benefit to satisfy this demand. But how can it be satisfied when the total sum of cash must remain the same? Simply as follows: with people valuing cash balances more highly, the demand for money increases, and prices fall. As a result, the same total sum of cash balances now confers a higher “real” balance, i.e., it is higher in proportion to the prices of goods—to the work that money has to perform.
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People will almost always say, if asked, that they want as much money as they can get! But what they really want is not more units of money—more gold ounces or “dollars”—but more effective units, i.e., greater command of goods and services bought by money. We have seen that society cannot satisfy its demand for more money by increasing its supply—for an increased supply will simply dilute the effectiveness of each ounce, and the money will be no more really plentiful than before. People's standard of living (except in the nonmonetary uses of gold) cannot increase by mining more gold. If people want more effective gold ounces in their cash balances, they can get them only through a fall in prices and a rise in the effectiveness of each ounce.