i grew up in pittsburgh, and had to leave because there simply wasn't a job for me - (most of the cmu startups threw my resume in the trash as soon as it wasn't cmu) though that was a long time ago and things have changed.

however, the numbers still show slim pickings. search glass door or any job posting website, you will find that philadelphia (not a tech city) has ~5x the amount of positions available. NYC has 15x. a lot of people retort about per capita openings, but I don't think that matters as much as people think. people do have geographic preferences but also apply to many other cities, and CMU graduates more engineers than pittsburgh has data scientist openings.

as you said, sure you have a 'lower' cost of living, but the jobs in pittsburgh pay significantly less.

pittsbugh is not a walk-able city, its one of the least walk-able ones that I know. Its almost 100% certainty you will need a car if you live/work in the city, and if you normally get around without a car, moving to pittsburgh and needing to buy/upkeep a car will wipe away most of those cost of living savings.

traffic and parking in pittsburgh is a nightmare. you can be in a car and see the building you want to get to, but not make it within 30 minutes.