One might also say that pre-ordering "incentives the developers" to not care about QA, and other important parts of the product and process, because they already have your money in their pockets... in fact, I would dare to say that the "pre-order culture" is largely responsible for the general mediocrity in the industry in the last 20 years (as compared to earlier "eras" of gaming...)
People give way too much credit to how pre order affect the industry when there's a lot more that happened in the last 20 years, that make way more sense than evil developers refusing to work on the game because they already got our money. One thing that have way more effect than pre order on the poor state some games are launched is the ability to patch after launch. That plus unrealistic deadlines and the financial cost of a delay means that a lot of bugs and issues are marked to be fixed after launch. They focus on anything game breaking or that might fail the consoles certification process, they try to get on a playable state with the little time they have then launch aware that the game have issues. They release broken games because they can fix later and because they set unrealistic deadlines.
Fallout 76 is a great example. You can bet Bethesda was aware the game had issues, so they let people play it on their B.E.T.A. event, already selling the narrative that the game will break, they launch in the established deadline hoping people will stick with it, after all, it's Fallout, then they will keep updating it, hoping that as the game improve, the playerbase will grow. It have little to do with pre order, which guarantee some sales but they still rely on day one and post launch sales to be lucrative.
This
article is about work condition on QA but it give some insight on this process, it's worth reading. Off topic but Firaxis seems to be an exception on QA work condition, they seem to value their QA a lot more than it's standard in the industry, at least that's the impression I have.
As for my pre order, I usually pre order a few weeks before launch. Why I pre order? Because I have no reason not to and if it's something I want to buy and play on day one to see if it's good or bad by myself, I want to be done with it and ready to play once it's launched.
will buy it when the preload goes up a day or so before release
Expansions and DLCs usually don't have preload.