First, you cannot currently install macOS on an iPad.
Second, strategies such as virtualization should continue working since mac virtualization shouldn't go away. And, Apple said that they would continue supporting their intel based macs for many years, and many people have intel based Mac Pro's, and I don't see them changing them in a few years since a investment into 30+ core mac's is a big investment.
So, in my opinion, that many years of support could surpass 10+ years.