The quote "No risk, No gain" is called from the quote "No pain, No gain", and actually, it does not only apply to gambling alone, it also applies to other aspect of life and investments like investing in crypto, stocks, and just about anything that carries with it some degrees or level of risk.
Gambling is risky, just about the same level as investing in meme coins in crypto, but that quote remains true as long as gambling and some risky investment is concerned, for normally, the higher a risk a gambling game carries, the higher the reward, but that also means ones chances of losing his or her money is also significantly higher.
Without taking risk, it's impossible to make money, or profit, just like for us to have a proper and healthy rest, we have to sleep, and while we sleep, there is no guarantee that we will wake up.
So, if we check it, we all will discover that we actually take risks every day, in different ways, risk is not limited to gambling or investing alone, even eating is a risk, for many have had their food choke them to death.
So, yeah, we risk something to get something, and in gambling, we risk money to get more money, but the chances of losing is always very high, and this is the reason why we must gamble responsibly at all times.