By "the Way Out of a Tech Downturn", he means that companies using more open source can save them money, and companies saving money is "the way out of the tech downturn"? And by "tech downturn" he means... "destruction of shareholder value", he's talking... stock prices?

I honestly don't think this has much to do with any reality.

I don't think any current "tech downturn" or reduction in stock prices specifically is caused by company spending on proprietary licenses; I don't think companies saving an amount of expenses equal to spending on proprietary licenses would have much effect on stock prices even if it occured (well, it might harm the stock prices of an companies selling that proprietary software if done on a wide scale!); and I don't even think that switching from proprietary software to open source can end up saving you the money he thinks it can.