The problem with Yanmar USA supporting the grey market is that one lawsuit for lack of a ROPS, lack of PTO protection, multiple speed PTO, or backwards throttle will eliminate years of profit on the parts. If they somehow controlled the tractors importation and brought them up to US safety standards, then they wouldn't have a problem. I am sure less than $1000 per tractor would do it.
Of course we know that they don't control these tractors. We buy them to get quality cheaply and either accept the safety limitations or fix the problems ourselves. Still, Yanmar gets sued and probably loses (and even if they don't, Yanmar runs up 100's of thousands of dollars defending the suits).
Blame the lawyers for filing suits where the individual used something improperly. Blame the juries for awarding large sums of money when the company did nothing wrong. Blame the government for allowing the lawyers to sue in this manner. Blame the US populace for being trained to expect every situation to be abolutely safe no matter what the person does. Blame the media for creating an expectation that some corporation or wealthy person must be responsible for any adverse event. Blame the lawyers for taxing society with these suits--which in most countries cannot be taken on a contingency basis.
I have seen the litigation effects on several industries. In airplanes, manufacturers were still getting sued for design defects in the mid 1990's for a 1929 aircraft. Most small aircraft manufactures just stopped making the small airplanes. Only when congress limited the industry to 25 years of libility for the airframe did Cessna restart manufacturing of light piston driven aircraft. Still, over half of the cost of the new airplane is manufacturers liability insurance. These days, kit airplanes, where the individual is the manufacturer (but it still has to pass FAA saftey standards) are 2/3 of the aircraft being produced each year in the US. The kit manufacturer has no assets and carries no insurance--so sue away--there is no money. A whole industry changed because of the legal climate.
Medicine in some states is becoming financially impossible. Florida is terrible for suits. There are only a handful of pediatric neurosurgeons left in Florida. High risk speicalty physicians (OB, orthopedics, neurosurgeons) often pay over $250,000 per year just for $1,000,000 of malpractice insurance coverage. Many physicians are just leaving the states with bad malpractice laws because they cannot afford to practice medicine. Without changes to the laws, some states may have good medical care and others may find themselves without many physicians. Some physicians put all of their assets offshore or in a trust so the lawyers can't get at it and run bare of insurance. Hospitals require insurance so surgeons can't do this.
In any event, the lack of personal responsibility and the societal decision that in any bad occurence there must be someone to sue is a tax on every product, service, and company in the US. The costs are incredible and the attorneys have a vested interest in keeping the current system and exploiting any new theory of a potential lawsuit.
Of course there are many types of law contract, real estate, etc, where the profession provides a needed service.
So much for my legal rant. Yanmar will never support the gray market units unless they are protected from liability. Eventually, you will be unable to insure a gray market tractor because of the liability (or it will be excluded from any homeowneres or business policy).