That's basic business. The bitcoins the ASICs manufacturers are sitting on is considered it's inventory. Company needs liquid cash to pay employees, taxes, cover their costs, and reinvest the remainder into expanding their business model. That would be EXTREMELY risky/suicidal for the CEO of a BIG ASIC company to try and raise more cash from the VCs (at i'm sure very unfavorable terms) instead of a logical thing, like selling your own inventory at profit. That's just not how businesses works. Sure small guys/solo miners in basement can risk it all, be visionaries and hodl until they make it big or run out of money, but not the big guys. Big guys need stability and to minimize their risks, and stick to their business model. What most likely is happening here is BTC are sold to VCs at a certain locked in rate and VCs are holding the burden of BTCs and the price fluctuation (after all risk management is what they do) and ASIC manufacturer can concentrate on their own business model.

VCs are not there to be nice. And because of their terms should be the last choice when raising capital, after your own capital, then loans from banks, then your last stop is VCs. They're not nice guys who give out free money, more like making a deal with the devil.