1. Seattle is quite safe. Friendliness is different than safety
2. It all comes back to housing density/supply. As you say, daycare costs are dominated by staffing ratios/wages - which are a function of cost of living. The surge of high income earners + housing supply deficit = pricing out daycare workers (and daycares).
Seattle has a higher homicide rate than New York or LA and it is running well above its own historical rate; in 2014, the entirety of King County had fewer homicides than the city of Seattle did in 2024. It is safer than many other US cities, but US cities are quite dangerous by first world standards which is why many people opt to raise kids in suburbia.
The required staffing at daycare isn't driven by "crime safety" but an overprotective sense of protecting kids from themselves and each other. These are the required ratios. As low as 1:4 for < 1.
A 4:1 ratio for infants seems quite reasonable and not overprotective. Children that age require a lot of attention. By the time you've fed and changed diapers for 4 babies it's about time to start the cycle again.
Having had kids and cared for them as infants myself, and previously worked in a (very much unlicensed) home-based daycare, the 1:4 ratio for childcare centers and 1:2-1:4 (depending on primary licensee's experience) ratio for home-based daycares for infants are not at all unreasonable.
Yes, most of time that's going to seem excessive -- but it is not a cloud system with on-demand autoscaling, you have to set your capacity by peak demand, not average demand.
2. It all comes back to housing density/supply. As you say, daycare costs are dominated by staffing ratios/wages - which are a function of cost of living. The surge of high income earners + housing supply deficit = pricing out daycare workers (and daycares).