As you read the news stories this week about Windows RT kicking the bucket, I think you should keep in mind that the app compatibility issues we currently have now with Windows RT is still going to be around with Windows 10.
The Verge reported yesterday that Microsoft had retired the Lumia 2520, quoting MS as saying "We are no longer manufacturing Nokia Lumia 2520." This followed about a week after MS stopped making the the Surface 2, marking the end of the unloved Windows RT variant of the Windows 8 OS.
Windows RT was disliked because of the compromises Microsoft had to make to get Windows on to ARM CPUs. They had to drop support for legacy Windows apps and limit users to only running apps which had been developed for Windows RT or Windows 8 (aka Metro apps). This cut users off from a few decades worth of still functional apps, and reduced the value and usability of any tablet running Windows RT.
So at this point we should be celebrating its demise, right?
Yes and no. Given that Windows 10 is very likely going to share a similar issue, this is simply a case of same stuff, different day.
Windows 10 is intended to run on PCs, tablets, and smartphones. This includes both ARM and intel chips, and that raises the question of just how much support the Windows 10 on ARM will have for the legacy PC apps which were written to run on Intel chips.
Based on how MS has avoided mentioning this detail, I wouldn't expect any support for legacy apps - just "universal" apps. And that means that Windows 10 on an ARM tablet or smartphone will have the same limitations as a Windows RT device has right now.
A reader pointed out this issue when the Raspberry Pi launched earlier this week (Thanks, Thomas!) and based on what I haven't been able to find online, I would say he's probably right. At the very least we can't assume support, and that strikes me as a good reason to avoid a tablet running Windows 10 on an ARM chip.
Luckily for us, this should not be an issue. Intel has been making headway in the tablet market, so I don't think it is very likely that any of the major tablet makers will even release a Windows 10 tablet that doesn't have an Intel CPU.
But if one does hit the market, I would avoid it until after I could confirm that it supported older Windows apps.
Or did I miss something?