I highly doubt that that Apple will remove dragable windows. Their iPad-ification of applications is the full-screen mode that can be toggled.
More likely: a bar-wide drag handler that takes precedence over widget clicking.
More likely: a bar-wide drag handler that takes precedence over widget clicking.
Why design the window twice inside of a year when designing it once will do?
Of course Apple won't take away OS support for draggable windows. That would be silly. What will happen, though, if the new full-screen mode takes off, is that app developers will redesign their windows to be more suitable for full-screen. And that may well involve smaller or nonexistent title bars.
I do agree, this could be a nuclear, apocalyptic scenario. But while photo, video and code workflows can be condensed nicely into one app, traditional mac workflows have been multi-window, multi-app in that most common tasks aren't IDE-oriented, and constructed from many different apps running on the Mac platform.
But, to counter your point about app laziness: most mac developers came to the platform to make really good apps. If it was about just throwing something easy out there, they'd have run to Windows or enterprise apps already.
The problem is that app UIs are going to pick a paradigm and it's going to feel out of place if you use a different one. The dragbar being replaced is a pretty good example of this.
It's a lot of why I'm not particularly looking forward to Lion.