Why isn't Linux configured to better preserve battery life on laptops by default? Power usage has been an issue for over a decade. If it's just a matter of a few tweaks, surely it could be done?
And then there are the hardware bugs which require workarounds in firmware or drivers, and the firmware bugs which require workarounds in drivers, all of which are only developed and tested against Windows.
The set of power management options that Windows 10 exposes to the user has been steadily dwindling to the point that on a new laptop you basically only get to customize how long before the screen shuts off and how long before it goes to sleep. All the more detailed options you had in early Windows 10 or in Windows 7 are no longer exposed, because there's no consistent way to map such controls onto the ever-shifting set of underlying platform features.
That and automatically activating a 'small speaker' EQ for when a device is detected to be portable / be a laptop and have internal speakers would be a massive user experience improvement for laptop Linux users.
TLP isn't magic. More than half of its documented options are inapplicable to current hardware or kernels, and a fair number of the remaining options that could still have an effect are not safe for distros to ship as defaults, usually because they'll trigger firmware or hardware bugs. Installing TLP by default would be far from an actual solution, and isn't even that great a first step toward solving platform power management inadequacies.
I'm sure a huge component of it is just people-hours spent in figuring out the right balance of defaults that don't just mess people's setups up.