Hi wp22. I totally sympathise with your view. I won't go into detail re my own journey, suffice to say I had endo affecting my ovaries, on the bowel, on the bladder, on the ligaments, on the uterus, completely stuck up recto / vaginal, on the diaphragm. Everything was stuck up and twisted out of it's normal position. My first consultant told me I was a 'complete mess'.
I have been endo pain free for 2 years and 3 months now following just the kind of surgery you are wondering about. I underwent a procedure called 'total radical excision'. This is where the whole lining of your peritoneum is excised away. This removes seen and unseen endo and fron the deeper layers. When it heals you have a clean new abdomen which is less likely to form adhesions than when patch work is done.
I think the real answer to your question is because there are not enough surgeons around who are skilled enough to perform what is quite gruelling surgery for the surgeon as it generally takes between 5 and 8 hours or longer. It is all done keyhole though so recovery is reasonably quick (between 4 - 8 weeks depending upon individual circumstances). You would think if should be the gold standard for advanced endo.
Like you are finding, drug treatment is only a temporary fix and does come with side effects. Once the drugs are stopped you will usually have to ask 'what's next' anyway or be back to square one within a few months. It can be useful in certain certain short-term circumstances.
Then there is laser surgery, (usually means the consultant is not skilled in excision surgery otherwise surely they would offer this superior procedure). What laser does is burns patches of endo off the surface. This causes scar tissue to form as it is a burn. It is a bit like cutting a week down from the surface. Often the roots will overtime just re-emerge elsewhere. Hence many ladies end up going back several month or, if lucky few years, later saying they think the endo is back. I have seen examples on here of surgeons saying "it can't be back because I removed it". If endo is only on the surface then it might well be satisfactory for some ladies, but generally it is deeper than that.
Many surgeons who say they do excision surgery do 'patch excision' which is what it says on the tin. Great it you do only have patches and they get them all. Trouble with endo is it can be unseen to the naked eye and it can be just below the surface. So again, ladies can be in the position if not all removed of going back for lap after lap for patches after patches to be removed over time.
For advanced stage 4 endo, removing patches might hit the jackpot and remove patches that just happen to be causing most of the pain, but you will still have endo. Same with hysterectomy - unless you just have it in your uterus, you will still have endo. Hysterectomy is generally only useful if you suffer from heavy monthly bleeding or other gynae conditions or have adenomyosis (endo in the uterine muscle rather than just on the outside) so it can be helpful for certain circumstances but not on its own if you have extensive endo.
I was also able to avoid a bowel resection because my surgeon was skilled enough to shave endo off the bowel rather than need to have a colorectal surgeon in tandem. He said a bowel resection is only necessary where endo has actually penetrated the bowel rather than having stuck everything up from the outside. He said in his extensive experience that was quite a rare ocurrence and is generally on the outside.
The operation that I had simply removed the endo and nothing else. I did not have to mess with my hormones, have a hysterectomy or bowel resection. I just can't understand why this does not become the standard treatment for advanced endo. But like I said, I believe it is because of the skill and gruelling dedication it takes to perform and there just are not the surgeons out there who do it.