The first question here is why there's a maximum speed you would like to be going. If you keep accelerating, you'll get there even faster! It's also not inherently unsustainable to make ever increasing amounts of money, because the economy can grow with you; it's not a zero sum game.
That said, you're right that a lot of companies totally bone themselves trying to grow unsustainably, letting the stability of their company (like customer happiness, employee retention, that sort of thing) fall apart in the meantime, and then collapse under their own weight. While I think the parent is wrong about how it applies to Quark, they're quite right that the incentives for short-term growth are driven by how the stock market works. It may have even tilted our whole business culture to worship growth regardless of context.
Here's how it works. Let's assume a simplified version of the stock market in which stocks are priced based on the current performance of the company [1]. So let's say I buy stock at IBM today for $188/share. IBM makes fucktons of money, which is great for IBM but useless to me. It's useless to me because that's what determined the price in the first place, so if it keeps on making the same number of fucktons then the price is going to stay at $188 and my money is just sitting out there doing nothing for me. What I need to happen is for the stock to be worth, say $200 so I can sell it and make some money. So I need IBM to grow. As much as possible. In fact, it's the only thing I care about, because after I sell the stock I don't care what happens to the company. So I vote to put people on the board who want to grow the company and they hire executives with that mandate (who are anyway paid in part with stock and thus have the same incentive) and the whole corporate culture aspires to growth at all costs. If they said "well guys, this year growth isn't really going to work and will probably just sink the ship, so we're going to spend our time making our customers happy and pocketing our billions in profits" everyone would sell the stock, the board would be fired, etc. So that's why you have to grow. [2]
[1] That's not really how it works; expectations of future growth are baked into the current price. Sort of. The relationship between a company's performance, growth, dividends, and the overall economy is complicated, but it doesn't really change the point much, which is that as an investor, you want the stock price to go up, and to do that, you need as much growth as possible.
[2] Following on from [1], there's the argument that in a world with perfect information and rational actors, if the expected future growth is priced in, then sacrificing long term sustainability for short term growth wouldn't raise the price. But we don't live in that world.