<...>
> and
> with the fact that some people who appear to like TextMate too umbrage at
> the suggestion that (for the people who prefer open source software, at
> least) closed source software suffers some limitations in terms of its
> probable longevity.
<...>

I can use real benefits Textmate provides for me *now*, and frankly, I
don't care about
any *probable* problems in the future. If TM gets discontinued - fine.
I still have my
copy, or I can choose from myriads of other editors, free or non-free,
open, closed,
dug-under-the-tree source, whatever.
I am pretty sure I will die one day, should that be the reason not to
use benefits of living today?
Cost of switching your text editor is much less than cost of
switching, say, your webapp infrastructure (some my argue), so
concerns about longevity should be viewed in appropriate context.

-- 
Regards,
Rimantas
--
http://rimantas.com/