What gets me is the attitude that you can practice on your own and "perfect" this skill over time. With all due respect nobody but nobody would suggest that you could become an olympic level boxer by yourself in a basement gym, but some are virtually suggesting that as it applies to self defense.
I have also coached soccer for 25+ years. The level of skill needed to disarm someone is higher than that needed to be a decent HS level soccer player. I defy anyone to take a weekend class, practice in the back yard for a few months, and then see if they could play rec league soccer at a HS level.
The hours of training it takes to be even remotely proficient in any martial art is incredible. You can go to the range for two hours a week and be fairly proficient in use of handguns, it takes more like two hours a day for at least 2 or 3 years to become proficient at a martial art.
I apologise in advance if my post offends by it's tone. The fact is I get annoyed when the hours and hours I have spent training gets belittled by those who think it is easy or simple. Besides, if it was easy my scars wouldn't mean so much and I couldn't impress they ladies.