The current production of Service Dogs is approximately 500 to 600 Service Dogs per year. That means that the current demand is approximately 1000 to 1200 dogs. That puts the current demand between 3000 to 3600 dogs for the next two years. If you then add 1500 to 1800 Service Dogs each year over the next 9 years, the ten year projection is between 16,500 and 19,800. These numbers are over estimates.
Many individuals are on more than one waiting list.
Even if you double or triple these numbers, assuming demand will increase with availability, the demand is less than 60,000 over 10 years. That's one tenth of the backward estimate. This is hard to quantify. Most Service Dogs are trained by non-profit organizations. This is because most disabled people can not afford the cost of a Service Dog on their own.