I am still curious as to why this doesn't lead to lots of gaming?
On many busy routes the difference between the cheapest and most expensive flight on the day can be £100+

So why not book the cheapest and then just switch to your chosen time on the day? Yes, there's the risk of it being full but in practice revenue management should push the price up enough for there to be space most of the time?

I guess people are probably too concerned about getting their chosen time to risk it, even if in practice most of the time they would get it