Why OSS from Big Corps is not treated as predatory pricing?

That boat has sailed. Twenty years ago, we might have called it "predatory" and anti-competitive. These days, it's just nature of the beast.

In a very real sense, Ballmer was right -- Linux and OSS were cancerous in their viral ability to demonetize the software market, but of course "cancer" is the wrong word given OSS's benevolence.

There's no question Sublime would have made more money without VSCode being developed as a marketing tool to funnel mindshare to MS's ecosystem (as "free" IE did for Windows). Same is true with all forms of easily replicable digitized product, namely music and movies. Bands don't make the kind of money off record sales like they used to.