I doubt it would have stopped politicians from exploiting the issue, but the answer to your question is yes. Companies could have spent more money on energy infrastructure, which would have increased their cost and - all other things being equal - lowered their share price.

That said, a lower share price is not a cost to the company, except perhaps in terms of stock based compensation.

If the market cap is based on future earnings growth (forward thinking) and those earnings are now couched by a lose of ability to build data centers then these tech companies could have issued shared or offered bonds to build out the interconnections they require. So, yes.

Stocks are priced on the margin, which means the last sale sets the price, and so the market cap for the whole float. The $440B never really existed. But it could have been used as collateral for loans which would turn it into 'real' money. However when the price falls, those loans may be called in, and so the 'real' money is destroyed. If these loans have to be be paid off by selling the stock, then we enter a deleveraging spiral.

Theoretically the market cap should equal the present value of expected future returns (dividends and buybacks, not speculation), modulo risk, but that assumes a perfect market.