Putting bad marketing aside, are there currently areas which would require another programming language, that would provide something current languages do not provide, or make it so much better that the change would be rational?
1. Yes, there are probably a lot of areas that need new
programming languages or improvements of the current
programming languages, everything is quite far from
"perfect" at the moment (and it will probably always
be). There's still a huge amount of research going
in this direction.
2. Learning. Should you ever be stopped from learning
something new by the fact that something similar
already exists? Probably not. This is just business
thinking utter bullshit.
3. This "resource" was the starting point before few
quite young popular programming languages. I haven't
read it myself but it must be something good to learn
from it judging by the outcome. Show some respect.