Is it true over the period of 2 years, even without treatment, for the majority of people genital warts will self clear and fall off?

Genital warts is caused by the Human Papilloma virus, the same virus responsible for plantar warts and cervical cancer. Preventive measures such as vaccination against HPV will significantly reduce instances of breakouts and cervical cancer. Our immune system can clear out the virus at times, as evidence in Pap smears that are abnormal with HPV one year, and then later normal without HPV later

No. It depends on the type and aggressiveness of the virus and a persons immune system. So it acant be predicted how and when it will go away.