It's definitely surprising that Qualcomm didn't. Not only does Windows have a longer tail of software to support, but given that the vast majority of Windows machines will continue to be x86-64, there's little incentive to do work to support ARM.
With the Mac, Apple told everyone "we're moving to ARM and that's final." With Windows, Microsoft is saying, "these ARM chips could be cool, what do you think?" On the Mac, you either got on board or were left behind. Users knew that the future was ARM and bought machines even if there might be some short-term growing pains. Developers knew that the future was ARM and worked hard to support it.
But with Windows, there isn't a huge incentive for users to switch to ARM and there isn't an incentive for developers to encourage it. You can say there's some incentive if the ARM chips are better. While Qualcomm's chips are good, the benchmarks aren't really ahead of Intel/AMD and they aren't the power-sipping processors that Apple is putting out.
If Apple hadn't implemented TSO, Mac users/developers would still switch because Apple told them to. Qualcomm has to convince users that their chips are worth the short-term pain - and that users shouldn't wait a few years to make the switch when the ecosystem is more mature. That's a much bigger hill to climb.
Still, for Qualcomm, they might not even care about losing a little money for 5-10 years if it means they become one of the largest desktop processor vendors for the following 20+ years. As long as they can keep Microsoft's interest in ARM as a platform, they can bide their time.