WIMP on hand held devices isn't great (ask early windows mobile). It's just too fiddly. But if touchscreen interfaces were better at a desk, we'd be doing that on desktops and laptops now. Touchscreens are readily available, it's just way more effective to have an interface that isn't occluded by using it.
Voice based interfaces clearlty work for some, but they're really fiddly for non-linear access.
The ergonomics of touch desktops don't really work. Lifting your arm (big muscle groups) and trying to manipulate fingertip sized widgets (fine motor muscles) in concert is very strenuous. There's a reason writing apologies on a chalkboard used to be punishment in schools.
For one-off activities or very short sessions it might work for some people. However the WIMP interface with its proxied inputs of a keyboard and mouse work far better for more people for longer durations.
Touch and direct input like a stylus works much better on displays that can sit horizontal (or mostly so). No matter how good a touch interface is, people just physically can't use them for long periods on a vertical display.
Yes, and if you set up a horizontal display for a desk, you're going to end up with neck strain. You could maybe do something at an angle, like a drafting table, but probably still balancing neck and arm issues. And you'd probably need to adjust display construction to reduce the distortion from viewing it at such a high vertical angle.
So the WIMP interface continues unchallenged... except for phones.
I used Siri on the iPhone for the first time in trying to return a lost property to its owner. The experience left much to be desired. Siri failed.
To break through that, a new interface paradigm has to be massively better - enough better that it's worth buying a new computer, a new OS, and all-new apps (from a very limited selection) to get it. That's an insanely high bar, which no alternative to the WIMP interface has cleared. So the WIMP interface continues unchallenged... except for phones. It's going to continue to rule the desktop/laptop world, though, and not because of "corporate greed". WIMP will continue because nothing is enough better to be worth the cost of switching.