So basically, add a table and a tablet becomes silly. That isn’t a good look for that device category. Who doesn’t have a table?

Now imagine how many of those people wouldn’t just use their phone while sitting on the couch or bed instead. Why should I use a tablet over my 6 inch phone screen? Why use a tablet instead of my TV?

The only two devices most people would need to own are a laptop and a phone. The tablet is an awkward third device that generally isn’t needed, or it’s a “cheapest possible laptop“ replacement for people who don’t need a lot of computing ability (emails, web browsing). Buying a Surface Pro instead of a proper laptop is itself a compromise.