Well, I'll disagree a bit there. The largest stock investors are institutional investors managing funds on behalf of retirement plans. Those investors tend to prefer consistent long term growth over a narrow quarterly growth target, and will actually look at things beyond just stock price, like strategy and long term market prospects.

Short term thinking from the leadership team is them not having a good idea on how to provide the long term strategy that investors prefer, and instead hoping to appeal to the smaller group of investors who do only care about short term growth so they can secure their own payoff, potentially at the expense of the long term prospects of the company.

Valve is a corporation. They have shareholders other than Gabe, many of whom are not employed at valve of in their leadership team. Their leadership team isn't looking to ensure that their paycheck comes in over the future of the company, so they make good choices.
Compare with companies like Coca-Cola, which are publicly traded but have that long term plan that lets them openly talk about sacrificing revenue to pursue product plans and market growth that leads to more stable long term profits.