I live somewhere in central Tokyo, and as long as I’m fine with a max 1hr commute I can reach pretty much anywhere else in central Tokyo (which is where the jobs are).
If your job is on the red line, and your house is on the red line, it's an easy commute, maybe 20 minutes. Calm, relaxing, easy to zone out.
If you change jobs, the new office might be on the purple line. Which does not cross the red line. So now you need to take the red line, to the green line (15 minutes + 10 minute layover = 25 minutes), and then change trains again to get to the purple line (15 minutes). That's assuming there are no delays, weather, construction/remodeling at any of the stations. If your morning coffee takes too long you might miss your connection, and now you've blown out your schedule by another 15-20 minutes, especially if part of your commute takes one of the less-frequent suburban lines.
End result is your 20 minute commute to your old office, has turned into a 40+ minute commute one way, assuming no delays. On a good day. Plus walking to and from the station.
My old office used to be on Castro Street in Mountain View, a 5 minute walk from the Caltrain Station. Then they leased a large building in the warehouse district, a 20 minute walk away. My old train commute + walk was almost exactly 1 hour from San Francisco; with the new office relocation it turned into 1 hour 15 minutes each way, which meant when I got home in the evening, the tram I wanted to take home had already stopped running, meaning either walk 45 minutes, or take a $9 (probably $15 in today's economy) uber home.
What point was he making? Well, switch jobs, and just move closer to your new office! Easy! Just never buy a house and only switch jobs at the end of your lease term, and rent forever.
Agree that you want to be living somewhere with enough employers within tolerable commute range, and obviously it's hard to compete with access to the whole world. I don't find a single change to be beyond the pale (maybe I would if it was a 10 minute wait), and I find that in dense cities with decent networks you can be in range of "enough" employers, but YMMV.
