If Microsoft embedded the GPLv2 terminal into Windows, Windows would have to release as GPLv2 (or compatible license). I assume they don't want that.
They can alternatively buy a commercial license, as another user said below.
You should read up on the "mere aggregation" clause of the GPLv2. It allows an OS to include a GPLv2 program without having to put the entire OS under the GPLv2. If the GPLv2 did function the way you seem to think it does, then almost every Linux distro would be in violation, too.
Why is that a problem? A GPLv2 terminal would not be a business problem for Microsoft. People would still have to buy licenses for Windows. Maybe they would lose a little face, but arguably they have already done so.
At least it’s not GPLv3 which this industry absolutely and viscerally hates (despite having no problem Apache 2.0 for some reason, Theo de Raadt is at least consistent).