At the very least, you could easily make an argument that a rising tide does not lift all boats; i.e. many people are personally not benefiting much from the tech-boom in the area. On the other hand, if your stance is that our collective goal should be to produce the greatest amount of good for the greatest number of people; then we want more people to move to the city have prosperous lives to fulfill the new roles available here. In that scenario it's hard to keep income inequality from expanding.
It seems like thusfar the city council has done a good job at striking a balance; MHA (mandatory housing affordability) is a level-headed way to redistribute some of the gains that tech has brought to those who are less fortunate. However, our current city council is much more left-leaning and I'm worried that their stance towards growth is far more "progressive" and anti-business.
Should people really be entitled to live in an expensive city that they cannot afford? Cities like Manhattan or SF have sort of taken a stance on that and it favors the prosperous. I'm not sure how I feel about the matter; but I certainly do not want us to dampen our potential future potential by encouraging businesses to set up shop elsewhere. We need more initiatives like MHA and fewer like the business head-tax.
I find it eerie that you're excluding from the equation the tens of thousands of homeless people in those cities. The right question is "to what lengths should we go to give people the ability to live with a roof over their heads?" The bay area has answered with "very little", where most people are barely offering human empathy to the homeless.
I do believe that we should support the homeless populations of our cities; but if you're familiar with Seattle's homelessness problems in particular, you'll know that the city has essentially thrown literally hundreds of millions of dollars at the problem to little effect.
I don't believe Seattle should follow a path of growth-at-all-costs and ignore the social problems the city has; but the city council here is staunchly anti-business, and that carries a risk-too, like the original commenter said—take growth for granted and you can end up like Detroit. In that situation, no one prospers, and everyone suffers; which we definitely don't want. It's a fine line to walk. That's all I'm saying.