I assume that they decided there was not enough use of Maple to
justify the expense of the license in CSC. The sentence indicating
that Sage will "replace" Maple is probably a simplification of
something like ...
"Those (few?) current users of Maple on our computer system may
find that Sage [SageMath], a software package we don't know too much
about, might satisfy their needs."
I think that someone with a considerable investment
in personally-coded programs in the Maple language would not
find that Sage is nearly a drop-in replacement for Maple. Also
be cheaper and more effective to license Maple for a workstation
for those who really need it. It is not entirely clear from the
Taito website, but it seems that a workstation version of Mathematica
is available. Also they seem to have a Magma license.
Beyond that, I don't know if they have any stance about free/open source or not.
In a larger perspective, I think that dropping Maple is not a positive sign.
Here is an apparently
major scientific computing establishment that has decreased its
investment in symbolic mathematical computing, presumably for
lack of interest.
I think it is not so much that they are "switching" but disinvesting.
What would be a positive sign is if CSC showed a particular
commitment to computer algebra systems or Sage by
(a) directing research funding toward such software development
and/or
(b) Offering specialized in-house consultation for CSC users
interested in Maple or its alternatives.
and/or
(c) supporting subscriptions to off-site services (SageMathCloud
which now appears to be CoCalc ?) for its user community.
I have not conducted a survey on the topic, but my limited
observation is that Mathematica, not Maple, has a larger
foothold in "scientific computing" establishments. Whether
this is an actual endorsement of the quality of the software
or a tribute to the dominance of physicists in national
laboratories or academia, or both, I cannot say.
RJF