Perhaps true, however the reason why many people invest is because they see a longer term vision of a highly usable currency. If you're only investing because you think others will see it as a store of value, then it becomes ponzi-like.
Even in future bitcoin is a highly usable currency, people would still not spend it often, simply because it is always rising in value against fiat money, so the usage pattern will quickly switch to save it and spend inflative fiat money instead
Suppose that I have a currency that increases in value almost 20% per year, should I spend it? No way, I would accumulate more of it. And when I want to spend, I will get fiat loan to spend, since the interest cost of a fiat loan can be simply paid by the value appreciation of bitcoin, and I still be able to get a few percent extra