There isn't really a "need" for maximizing it, that's the point. It already makes me enough money, why would I take any risks by doing anything bigger. I understand that some people may want to have something different and they may want to have something that is special but that doesn't mean that its going to be true, and you may end up with a loss. The reality is simpler, you are going to end up trading and you will lose the money.
Not entirely true, people who have a vast knowledge and experience in trading rarely lose money. And if the option for maximizing return is given, most people will take it since it is the natural aim of investors and traders.
But, I would agree with your belief that it is better to have part of the possible maximum profit if we are free of risk of losing all of our investments.
This isn't a sure thing of course, you could trade and lose some money as well but there isn't really a guarantee to that neither, and you could end up losing money as well. Instead of that, you could just end up holding, which would definitely get you profit if you hold long enough. The trick with holding is that sometimes you have to hold just a bit, and sometimes you have to hold for a long time but at the end of the day you are going to end up profiting one way or another.
We cannot profit by holding only, we have to sell at some point to realize our profit and then we buy again at the lower price. This is the essence of investment and taking advantage of the volatility of the market. Thus, we have to trade, buy and sell although it may take time for us to do the trade, it isn't a bad move to wait for the price to hit our target selling price and at the same time the target buying price to reinvest and repeat the process.