I said easily, I didn't say risk free. I also didn't say put everything in stocks. Stocks are extremely overpriced at the moment, and only a small of my portfolio are in them. Investing is a hobby I spend some time on each week.
I'm just pointing out that you should calculate the gain you could personally make from your capital and account for that in your decision.
Part of that equation is the time and knowledge required to invest that successfully, which not everyone has whether the time, the knowledge, or the time to acquire the knowledge.
I don't know why you think I insinuated it was impossible. I'm not a wealthy person who enjoys finance so it's reasonable that I would not expect to see gains like that.
Stocks, bonds, currencies, property, alternative assets (i.e. acquire a profitable something, invest in passive income assets such as solar energy SPVs, music royalties, etc)
It still takes a time investment to achieve that. There's no free lunch.