I don't think the average software developer in the US is paying anything close to the average rate for rents or mortgages, so I'm not sure how you think UBI would help keep them afloat in between jobs.

Financial discipline doesn’t help you with a cracked filling or a broken arm.

If you’re really honest with yourself, and us, the people who say they can’t afford to quit their job (for financial reasons) we think less of those people. It’s not because we’re petty, it’s because they’re living beyond their means in a profession where that is just so dumb you have to question their judgement on other things.

If they say they have to stay because they need the insurance (for themselves or especially their family) we collectively groan and bitch about the state of medicine.

UBI for devs isn’t to pay rent, it’s to lower your burn rate between jobs.