I think it's plausible you would want to use Chapel for every program you write. I definitely want to use it for every program I write, but I'm also biased.
The main disincentive to doing so today is that Chapel is not nearly as broadly adopted or well-supported as the languages you probably do use in practice today. The Chapel team is trying to get it to that point, but it's a modest-sized team taking on large challenges (both technical and social, as this thread indicates). To date, we haven't made a significant effort to draw in a massive/mainstream audience because we know we're not ready for it yet, either in terms of the language's maturity or our ability to support a large group of users. But we hope and intend to get there.
That said, I think we're already achieving the aims in the slide you quote—far more than your easy answer suggests—though there's obviously room for differences of opinion (e.g., what does it really mean to be "as programmable as Python?"). If you're interested in pointers to supporting details, let me know.
The main disincentive to doing so today is that Chapel is not nearly as broadly adopted or well-supported as the languages you probably do use in practice today. The Chapel team is trying to get it to that point, but it's a modest-sized team taking on large challenges (both technical and social, as this thread indicates). To date, we haven't made a significant effort to draw in a massive/mainstream audience because we know we're not ready for it yet, either in terms of the language's maturity or our ability to support a large group of users. But we hope and intend to get there.
That said, I think we're already achieving the aims in the slide you quote—far more than your easy answer suggests—though there's obviously room for differences of opinion (e.g., what does it really mean to be "as programmable as Python?"). If you're interested in pointers to supporting details, let me know.