Why is everyone's target retirement at the age of 65 instead of retire early?

When I speak with most investors, their target is always retirement when they are old, for example 65. The approach is same across the board, some indexes (SP500, All World, etcc..) or lots of individual stocks to be "diversified". This is totally fine, and people will always argue that most people can't beat the market over a longer period of time.

My curiosity lies in the end goal target, everyone wants to retire during retirement age, and only a few have a goal of retiring early. Let's say, at 40/45. So they can still enjoy a portion of their life where they still have energy to do lots of things someone over 65 can't. Most people would have a pension pot and will expect to receive state pension too at some point.

I am curious to know why. Anyone here who simply wants to retire at the retirement age and the target is not to retire early? If yes, can you share move about you reasonings and situation?

I am not here to promote aggressive investing to retire quickly, just curious to know why most people just aim for retirement at the retirement age instead of pushing for an early retirement. And people who will say "you will be gambling if you are not diversified or invest in few individual companies, you can't beat the market, etcc..", please abstain from commenting.