I don’t think that’s the case though. What he says he could do this in a weekend, he usually does (for instance, he was annoyed with Powerpoint so much that he made his own slideshow program in about two days of programming time). And when he said he’s gonna build a compiler for his language, he didn’t say it will be quick.
His point with the Windows terminal is that, its a non-problem that people in the 80s and 90s already figured out. And if he really wants to make a terminal with the bare amount of features that he just needs (without the flaws the old cmd program has), he may be able to do so in maybe about a week (he already has code to render TTF text, and he’s probably accustomed enough to the quirks of the Windows OS APIs)