So… why would you do a bottom tier job for terrible compensation if it’s no longer necessary to survive

If you actually think about which actors do what and what their incentives are, this question really answers itself. Let’s take an example: cleaning toilets. Many people will stop doing the job. The owner of a small business will start cleaning the toilets themselves. They will clean the toilets less. A person with a higher wage will clean the toilets if it is still necessary to the business to keep them clean.

Small business owners already tend to clean their own bathrooms or delegate it as a minor task to an employee. This isn’t a particularly helpful answer

> So… why would you do a bottom tier job for terrible compensation if it’s no longer necessary to survive

You wouldn't: bottom-tier dead-end jobs would see wage increases, because they'd still be necessary, but no longer have an economically coerced labor supply; Jobs that have too marginal economic value to be viable in the current minimum-wage set up, but which provide useful experience and thus are not dead end jobs woild become viable, and because more people would be able to take time out of dead-end jobs to do education and training, competition for entry level jobs in fields with advancement would be greater, likely suppressing wages in those jobs.

If the wages rise then prices rise and then you don’t have basic income anymore