> I believe in the fundamentals of investing in stocks because in all it's technicality (and given the buy-and-hold strategy), you are investing in a business by owning a part of it which naturally means that you will and do get the returns on it, both in terms of profits (dividends) and and value growth (appreciation of the stock value). And conventional wisdom of lending also applies to bonds.
Except that is not technically true. Unless buying stocks purely for dividends, you are investing in a secondary market of shares and the "value" you're talking about is the expected value the other secondary market participants will appraise the stock for, independent of the company's operations. There is only a directional correlation because there is a tacit assumption between the investors to equivocate between the two. If you look at the historical trends of P/E of S&P composite price index, prices have gone way more up than the actual earnings.[1] so there is an element of wishful self-deception here.
Consider this; bitcoin might one day build enough track record to prove itself a good enough investment for a large amount of people, and then the stock market will have to seriously compete with this non-derivative instrument for investment money of those people, which will reduce the price of stocks in aggregate, independent of the "value" of underlying company performances.
If you take that into account, crypto-or-not a currency is simply another instrument which we bet for the future expected value for gains. In fact, while the value of traditional currencies are backed by their purchasing power performance in a given market, crypto currencies theoretically don't have that limit because it has unlimited supranational reach.
Mind you, US stock markets have at most one century of roughly-comparable historical data, and that is just not enough sample size to make 30-50 year assumptions (speaking for retirement buy-and-hold strategies).
[1] https://en.wikipedia.org/wiki/Stock_market#/media/File:IE_Re...