The only reason to buy or own a stock is to make money.
I see a lot of people whose reasons for buying or owning a stock resembles the following justificatons:
"Are they going to be here in 2 months/years/decades from now? Of course they will." "Will they still be in business? Of course they will." "Will demand for the company's product increase or decrease over time? Obviously, increase." "Do you think this company's product is the future or do you not? I'm betting that it is." "Do you think this company is expanding or contracting over time? Obviously, they are expanding. It's a great investment opportunity."
None of these things have anything to do with what the market prices the stock at yet these justifications are used to own single stocks with idiosyncratic risk. You can be completely right about the importance, durability, and forward progress of a company but the market does not owe you an appreciation in stock price (the only reason to buy or own a stock) in exchange for that accurate judgment.
Companies are resilient but they optimize for their survival and revenue, not the spot price of their shares on the stock market. It's true that a Google or an Amazon will likely survive WW3, the dollar going defunct, a second tech bubble bursting, etc, but that does not tell you anything about the opportunity or opportunity cost of buying and holding shares of their stock.
I see a lot of people doggedly sticking to their plan through huge drawdowns because they trust in the company. You can be totally right about that trust but it has no relevance to the performance of the stock. A company's marketcap can be cut in half and they can be operating perfectly fine, business as usual, even if that stock price never recovers for the entirety of that company's existence.