Why English teaching is considered a dead-end job in Japan

From a job site:

Language instructors generally need no skills other than being a native speaker of the language with a 4-year college degree. Working Holiday or Spouse visa eligibility can be substituted for the 4-year degree.

This is an unfortunate fact of life here. It isn't necessarily a loser's job, although many Japanese and foreigners consider it to be so, it is simply the best paying job open to the majority of native English speaking residents in Japan. Of course you could be a waiter or a bartender at less pay. Perhaps you can start your own non-teaching business. Forget the salaryman fantasy even if, like Tom Cruise, you become more-Japanese-than-the-Japanese. Best case---you get on with a foreign company as a local hire. Not easy and requires a lot of networking and a lot of luck.

The biggest waste of time and money in my life was the year that I returned to college to get a TESOL certification (one which could be used for teaching in the U.S.) before returning to Japan to what I knew was a ad career destroying move. I hardly use anything I learned, and if I actually tried, I would piss off many "students." A good CELTA certificate is more than one needs here. In fact, because it focuses on practical aspects more than SLA theory, it is probably more useful than what I got. As I have mentioned, even the simple rudimentary Berlitz basic instructor training is MORE than sufficient for the vast majority of jobs.

The skills you really need are:

• customer service (ass-kissing or groveling in some cases),
• entertaining skills (make it "fun"),
• the ability to tolerate people who make foolish/racist/sexist statements without getting losing your cool or openly challenging them. If someone looks you straight in the eye and says, "Japan is the ONLY country in the world with 4 distinct seasons," you MAY NOT laugh and call them a "retard."
  
• the ability to make people feel relaxed, to be nonthreatening,
• patience
• not take offense at subtle or not-so-subtle insults
• enjoy debating trivia (the British say "in main street" but Americans say "on main street." Which is correct, "that" or "which." You cannot openly say "I don't really give a flying f**k." You are teaching "communicative" English. BAHAHAHAHAHAHA)
• The ability to endure a dead-end job with no future and no real opportunities to advance or make more money. A job in which the standard salary has not increased since at least the 1980s.
  
• endure being seen as a baka gaijin , who although entertaining, can't really be taken seriously.
  
• teach attractive women without assuming that they want you to date them or have sex with them. They don't want that anymore than an American, British, Canadian woman would. You will have to check with a female instructor for any advice specific to teaching mostly Japanese men as a female.
• Ideally, you should be able not to take a student's physical appearance into account when teaching them, however I knew many who did at Berlitz and still seemed to be successful. Let's pretend it is valuable skill here.
  
• able to pretend that a lazy, time-wasting student who would fail or be thrown out of a class in your country is a good student. (Most places will not let you evaluate a student as less than average which is usually called "good" here.)
  
• Understanding that just because someone is polite to you and laughs at your stupid jokes, or even says that they enjoyed your class, does not necessarily mean that they did enjoy it or like you.
• As a few Berlitz Instructional Supervisors told me: " Just make sure they have fun and "think" they have learned something." This is the bottom line, although it is not what would be considered teaching in the West. (If you are doing a company course---especially for foreign companies, their HR may hold you to much higher standards than Berlitz et al. Still, good luck on getting people to seriously study. Some will. Most won't.)
  
• Finally, for you own sanity and self-respect, the ability to find something outside of the job to provide meaning, challenge, and direction to your life. Find something to keep mentally and intellectually challenging. Stay physically active and fit. Otherwise you will become a fat idiot, although this will not in any way disqualify you from most teaching jobs. The idiot part may even help. So far, I have not become fat.