Is a PhD worth doing?

If you can get the job you want without a PhD, do not do a PhD. It's 4-8 years (no set length, so no guarantee you'll be done before 30+) of 60+ hours a week work for low to no pay. Most programs will not let you work on the side. You'll never finish if you try to hold down a full-time job at the same time. They have high drop-out rates and are extremely stressful. You don't need it, so don't do it.