One thing I should mention is that physician salaries have actually increased in the past 10 years, while dentistry salaries are on the decline and will probably continue to decline.
One of my classmates owns his own dental practice. If he takes a day off, he loses about $800 a day just to keep the office open and his employees paid. He has to pay $1800.00 a month for health insurance for him and his wife. These things all add up. Plus, dealing with all the headaches of being an owner including employees, taxes, regulations, landlords, disgruntled patients labs, suppliers, marketing/accounting, etc.
Though I would say that physicians generally have more stressful day-to-day jobs and generally deal with more stressful clinical situations and much higher likelihood of getting sued. Though I bet being a dermatologist is sweet (salaries in the 300-400,000s, benefits, regular working hours, etc)
If you plan to work for someone, then yes, medicine is probably a better path. If you plan to own, dentistry is better. It's the path of less resistance and more gain.
Of course there will be expenses even if you're not open and 800 dollars in fixed and variable expenses is not too bad when comparing to how much you are making when you are there. 10,15, or even 20k+ days produced per dentist completely overrule that 800 (or 1800 to health insurance) dollars that were lost that day and compensated by your daily production on other days. I would be more concerned about potential lost production for the day missed, rather than the expenses incurred. Being an owner is more fun than being a slave to someone else but most of what you mentioned are found with any business. Even as an employee, you'll have problems with other employees, regulations depends on the state you are licensed (regardless of employee or owner), interaction with landlords are typically kept at a minimum, disgruntled patients is with any medical/dental profession, suppliers (inventory management is not difficult unless your suppliers are fly-by-night operations, you shouldn't have problems keeping in stock), accounting (quickbooks/bookkeepers/accountants), marketing (just be personable with mass marketing), etc...All of what you mentioned are "headaches" are relatively simple and not real headaches. I hope what I'm saying makes some sense.
Why don't I want to be a physician? More work and more liability. The points below should articulate why:
- You have to work a lot harder in undergrad, take a lot more difficult entrance exam (MCAT), and do all sorts of annoying activities even if you don't really care about them just to appear well rounded. Not so much in dentistry. 3.0+gpa with prereqs? More than sufficient to be considered for admission in a dental program.
- Medical school board exams are probably way harder than dental board exams. You have to study really hard and suck up to everyone to get into a lifestyle residency such as dermatology. That entails working a lot harder than if you were going a GP route and doing more of what you did in undergrad to stand out.

- Way longer training. 4 years is already long enough, imagine piling on more years.
- If you don't get into the lifestyle residency of your choice, you have to work a lot more hours at the worst times of the day for the rest of your career. Same with dentistry though, if you're gunning for a residency of your choice, and you don't get in, you'll probably hate your life if you hate being a GP.
- Liability. The chance of you killing someone is really low, sedation is probably the highest chance of killing someone outright... and I don't sedate patients.
These are my reasons as to why I prefer dentistry over medicine. I'm not going to say medical doctors are worse than dentists. In fact, I believe we should respect them more because of what they go through and what they sacrificed to help their fellow man, because for me, it makes no logical sense since it requires more effort for the same or marginally more gain. As someone mentioned in a previous thread, there's someone who has to do neurosurgery/oral surgery... just not me.