Which is why changing jobs is the only way to get paid what you're worth: management has neither the backbone nor the incentive to price things properly. So instead we perform the cognitive hack of two underpaid employees trading jobs, because as you said, "The easiest time to give an employee a raise is during hiring."

I figure the only way to really fix this 'the only way to get a raise is to leave for a year' method is to figure out how to include retention in engineering manager's perf evaluation.

Putting retention in the manager's evaluation without also supporting his efforts (e.g. with an appropriate budget) isn't fair to the manager.

Oh, well then I guess we'll have to continue underpaying employees.

And employees will continue their migration outwards to other firms. They'll tell their (now ex) coworkers about how much better they're paid elsewhere, and those coworkers will start to sniff around as well. It's a lose-lose situation. If employee retention is the goal, better to strive to pay top-of-market (see: Netflix, most small/medium consulting firms) than let your best and brightest be woo'd elsewhere.

Your comment proves the point of the article. As long as the management refuses to pay a salary that is at par with the market standard, the only way to get paid as per the market standard is to get a new job.

Yep. Since I graduated from college 6 years ago, my compensation has increased 165% (starting from mid-five figures). How? By switching jobs every couple of years, and always increasing by a minimum of 10%. And honestly, I'm just getting started. Though my hope is that my current employer makes it worth my while to stay for a longer duration. I'm getting tired of switching every couple years, as is my family.

A lot of employees would gladly choose to stay at their current company if the pay raise was fair. It's not easy for people to uproot their lives every 2 years. But there has to be an actual incentive (financial) to staying at a company long term.

Why would they have to uproot every 2 years? Many (the majority of?) tech workers are close-ish to big cities with healthy tech scenes, and remote work is very much 'a thing' these days too. Live in Seattle, get paid for work done in LA, SFO, Portland, etc.

Not everyone is interested in remote work, including IBM. Not everyone lives in big, tech cities. There is an inherent transition cost when switching companies.

This only works if the employees can get competing offers which are 20% raises though. Surely if your employees are worth 20% more on the open market then they shouldn't stay anyway?