I haven't seen any data on it, but that's my understanding as well. (>1x is rare in today's market). But the NYT article does mention Honest Co. with a 2x on $1.7bn valuation, so there's at least that anecdote.
Actually I have heard/read that it gets more common in very late stage (near-IPO) financing rounds as well. For example, when a company is expected to IPO in the next 12-18 months but needs some more cash runway, there are funds that specialize in providing this type of "bridge loan" financing, which often comes in the form of preferred stock with heavy liquidation prefs.
Yeah, the fact that they have to cite Honest Co. (not one of the big names), and that the liquidation preference works out to a tiny fraction of their current valuation, suggests to me this isn't a huge concern.
Then again, I don't know how transparent the financing is for these enormous companies, so maybe it is a bigger deal than I think. (I also don't lose too much sleep over it.)