Loyalty is not an anathema to a non trivial company, but it needs to be a core value practised across the board not just in part of the firm. It's just like altruism has been shown to be a benefit in natural selection (somewhat counter-intuitively), being a loyal employer has all sorts of benefits to the company. The problem is that it doesn't work with the aim to be a unicorn - you can't grow massively, you can't risk the company on a play. Those "plodding" companies a step removed from the white heat of capitalism, the ones whose owners are "quite rich enough, thankyou" and don't sell, the ones whose employees do spent decades working there.