At which point did you stop speculating and start with a consistent diversified strategy?

Hi all, i see many posts of people on Reddit investing in single stopcs, hyper sector concentrated etfs etc. And that makes me wonder, at what stage of life or net worth amount do you/do these people stop making stock/sector bets and instead use broad market indexing founds for peace kf mind while focusing on life, high savings rate and consistency of investing?

What i mean os, I could understand whi had 5k to invest only and wants to make a bet to make it big or loose it but those with 500k/1m+ why not just invest in the broad market and do the compounding and consistency of investing do the work without that extra risk and stress?

I know people have different goals, some have a gambler spirit, others a low risk tolerance, but to me it sounds crazy that someone with 1m for example would choose to risk it rather thab see the fruits of compounding and diversification do the work.

Curious to see from those of you in here who has been a "gambler" and then later a diversified passive investor and what took you to get there.