If they were to focus on core business would this necessarily be a bad thing? Would it stifle innovation (bad) or reduce technology churn (good)?
Google or Facebook won’t improve their margins by releasing more or less OSS. Business models and software licenses are orthogonal. If anything, we might see an uptick in open-source activity as a glut of recently laid-off engineers suddenly find the time to work on passion projects.
Another way to think about it is, why does big tech open source anything? Leveraging a free, global workforce, competitive strategy, good PR, recruiting, karmic value are all good guesses, but I don’t think stock valuations play a big role.
Software aside, economic downturns typically spur innovation as founders with good business models find both talent and capital more easily. If you cross-reference the founding dates of many successful companies with economic cycles, I think you’ll be pleasantly surprised.