Likely will always have a desktop. Just bought a Mac Mini M1. iPads just don't have the longevity of Mac desktops. My 2009 Mac Mini is still fully functional and has good performance. The iPad from the same time period (iPad 1 released 2010) is now really totally useless.
In all fairness, that 2009 Mac Mini has around the same CPU performance as the 2014 Air 2. Iirc, Air 2 was around 8x the speed of the iPad 3 so I could imagine just how much worse the A4/256MB RAM OG iPad was. The Air 2 was a turning point for iPad longevity.
With that said, being reliant on batteries is a con for mobile devices longevity-wise versus desktops.