To the job of terminating people
My view is that hopefully that job will be done by doctors who are regulated and have some code of ethics. There are doctors who offer that service in other countries because they believe in people having a right to choose but I don't think a doctor should be forced to do it if is against their beliefs. Of course that could be problematic because a service to the public sometimes seems to involve carrying out government beliefs rather than your own so I am not sure what safeguards there would be for people who have a moral problem with killing a patient that wants to die.
How does any business maximise profit
By promoting itself, by being competitive and by lobbying government for a favourable environment for it's own business
Yes I can see the danger of culture and advertising influencing people's moral beliefs. They are currently influenced to prolong life despite the patient having expressed that they would not want to live with what they feel would be an unacceptably poor quality of life. So it is entirely possible that people could be influenced to not prolong life. I think people should be able to exercise their choice and leave instructions after discussions with doctors who can explain what to expect in clinical terms in various scenarios. Discussions may allow doctors to ascertain if the person is being pressured by relatives in their choice.
Pain is a problem but it comes down to allowing pain and killing. Not sure by what you mean by humiliation. Who is being humiliated?
When you are incapacitated, taking care of your daily needs and not being able to function independently can feel like you are losing your dignity and feel humiliating for some people.
Also, lack of funding and number of patients means there are delays before nurses can administer pain relief to people in pain - some people may choose to check out now rather than prolong their suffering and loss of autonomy.