Samson Mow, a Bitcoin maximalist and head of JAN3, has publicly questioned the sustainability of Zcash's current parabolic surge. He believes that Zcash's market valuation is artificially inflated, and the market will inevitably revert to the mean, with insufficient speculative capital to maintain Zcash's position in the top ten by market capitalization. Mow pointed out that Zcash has risen over 1,000% this year, and its privacy coin market cap is overvalued. These comments come as Zcash developers activate the NU7 upgrade on the testnet, aiming to triple block generation speed.