FWIW, I would not go pro if I had it to do again. I am a DM, and really the only thing that gets me is air fills, tips, and the obligation to guide a bunch of people who are sometimes very bad at diving and very demanding, which makes me an underwater babysitter/steward. I have a graduate degree in education, so I am pretty well versed in the various methodologies of didactic instruction, supervision, and blah blah blah. I feel like my background in education adds a lot of value to new divers as I know how to teach for a living. However, that value does not typically get returned to me. It costs me about 125 bucks a year to keep my DM card active, plus another 300 bucks a year for insurance. If you add up all the tips that you make assuming that you lead a full six passenger boat EVERY weekend (which won't happen) and factor that every diver will tip you twenty bucks (which they won't), then you can feasibly (though not likely) make 120 bucks per weekend, for a total of 480 bucks a month. Multiplying that by 12 gets you 5,760 dollars per year, which unless you live in the PI is not enough with which to sustain yourself. Keep in mind that you are going to have to buy dive gear throughout the year, which even at keyman prices pretty much takes up all the money you just made from tips once you subtract insurance and dues to PADI. I am not an instructor, but this is the reality of being a DM in the southeastern United States. We have it better than a lot of people.
Making a living diving is a nice thought, but unless you want to live like a poor person, be single forever, or live in a foreign country, you are better off getting a CCNA, welding certification, your EMT-B, or some industry certification in your field for a real job. Make good money at your day job, and dive for fun and as a hobby. There's no law that says you cannot help out a shop or club as a DM or instructor in your off time. I do that, I just do not depend on it for money to eat (which is good, because I would not be eating very much if I did). You will also find that you are a lot nicer to people on a dive boat when you are there because it if fun, not because it is paying to keep your electricity on in your 400 square foot apartment.
Making money as a reg tech and retail guy isn't too terrible, I've have done it a bit and I have a few friends who still do it. You will make about 25,000 thousand dollars per year if you have a great job in retail diving, which is not enough to sustain you. You will also need to work retail, which for many of us is a fate worse than death. If I worked at another dive shop it would only be part time for beer money. Besides, the more time you spend at a dive shop, the more crap you buy and the smaller your already small paycheck becomes.
This is what you listed:
Dive as much as possible
Travel the world
Gas Blending
Tech Diving
Photography
Work on a boat/Live aboard
Help out with people who want to dive or learn
Work in a LDS fiiling tanks/ servicing equipment etc. (Note that tank monkies typically do not get paid, but techs do)
Open my own shop one day down the road.
Of the above, the following do not pay you any money unless you are certified to teach them:
Travel the world
Gas Blending
Tech Diving
Photography
Help out with people who want to dive or learn
Of the above, the following will pay you a substandard living as a DM or OWSI:
Dive as much as possible
Work on a boat/Live aboard
Work in a LDS fiiling tanks/ servicing equipment etc.
Open my own shop one day down the road.
YMMV. If you really want to do it that bad, you will not listen anyway. I didn't, but now I have a fancy wallet full of plastic cards and a job that doesn't involve diving for a living