They don't, bacteria can evolve quickly because they multiply a lot. Humans take about 30 years to create offspring so evolution is pretty much nonexistent on the scale of a human life
The same is true for shaving gels/creams. I wasn't really sure what the point of my shaving cream was, only that my skin started to itch the next day if I used it. So I tried to shave without it and lo and behold, it's fine without. I notice no difference in shaving, but my skin doesn't itch anymore and I use 1 less product
Yes you can unlock the bootloader (not supported on the Japanese model and there is no US model this time), I'm not sure how well the camera system works on a gsi. On previous models they had to use proprietary blobs to get it to work properly
All those lockscreen features have been a thing before, but got removed for some reason