They mentioned they were happier having enough money to get out, but not actually getting out. Maybe that’s the difference? Just knowing it’s an option?

It definitely makes a difference knowing you have the option, the startup I worked for exited last year leaving me with a significant but not life changing windfall from cashing out my options. I'm still in the same job, but now working for a big corporate, and some days I absolutely hate it, but I at least know that I'm here by choice rather than necessity. Should it become too much I've got enough money in the bank to just rage quit and walk away without needing to immediately find another job.