Macs are not "legacy computing". Try using an iPad to do any sort of real work for any length of time; you will want to throw it at a wall. You still need a Mac (or even a Windows or Linux PC, let's be fair) to do real work. You still need a real computer to do software development.
Like it or not, iPads and iPhones are best at consuming content, communication, etc... They are not good productivity tools. Sure, there are things you can do on an iPad, but once the scope of work becomes more involved, you're going to want a real computer.
If I had to depend solely on an iPad to do my job I would go crazy in short order.