all the above reasons
desktop s/w is $200mil revenue and 4mil users which is not nothing, but it's somewhat a legacy business now, and only 1% of their revenues and declining 5%, while online/live and other business areas growing 10%. in the last earnings statement they referred to yielding share for "low average revenue per return" users and seem fine with that as long as there is growth in higher revenue areas.
this year they are killing desktop basic edition which likely most overlaps with online capabilities, ItsDeductible, Win10 and Mac OS 13 (not unusual for MacOS as they have been dropping support for an OS version and certain hardware annually in recent years).
Intuit has also been lobbying hard to kill IRS Direct File which appears to be in the works, and likely hope to capture those folks into online.
I would also think this decision was made in conjunction with MSFT to help project what % of users would convert or be lost, and help influence/accelerate Win 11 adoption within the significant Intuit user base, while simplifying support for Intuit in what is now a legacy business.
So the bottom line is Intuit doesn't mind what you do - upgrade to Win 11 in next 6 months and continue to use Turbotax, or upgrade in 12 months or never, use their desktop s/w or don't, move to online or competitor or don't - they are focused on the other $20bil of revenue and will do just fine.
