600V/600A is really pushing it even with IGBTs.
What? 
https://www.infineon.com/cms/en/product/power/igbt/igbt-modules/fz3600r17hp4_b2/
This thing is actually a module made of several IGBT transistors. We were kind of talking about single transistors - at least I was - since that was compared to some DIY module made of several MOSFETs. So, that's just a module too. And that's why I mentioned one of the beefiest, yet single discrete MOSFET transistors I could find. Finding off-the-shelf, single IGBTs with those specs is harder.
And I didn't say those didn't exist. I said they were few and VERY expensive. The module you referred to is about 1500 euros. Holy crap. Even a 600V/400A single IGBT is around 100 euros or over.
So point is related to the original video, the idea of making a custom module to cut cost is not necessarily stupid. Just happened that they didn't design it properly, but paralleling several MOSFETs instead of using a huge one is relatively common, and suggesting an IGBT instead here, unless you have a very good technical reason for doing so, is debatable.