Clinical trails have to follow specific guidelines,...

Clinical trails have to follow specific guidelines, implementation of new technology regardless of how good it is, isn't easy. It can take years to successfully reach phases III and IV.

"Phase I Clinical Trial

Phase I clinical trials are done to test a new biomedical intervention for the first time in a small group of people (e.g. 20-80) to evaluate safety (e.g. to determine a safe dosage range and identify side effects).

Phase II Clinical Trial

Phase II clinical trials are done to study an intervention in a larger group of people (several hundred) to determine efficacy (that is, whether it works as intended) and to further evaluate its safety.

Phase III Clinical Trial

Phase III studies are done to study the efficacy of an intervention in large groups of trial participants (from several hundred to several thousand) by comparing the intervention to other standard or experimental interventions (or to non-interventional standard care). Phase III studies are also used to monitor adverse effects and to collect information that will allow the intervention to be used safely.

Phase IV Clinical Trial

Phase IV studies are done after an intervention has been marketed. These studies are designed to monitor the effectiveness of the approved intervention in the general population and to collect information about any adverse effects associated with widespread use over longer periods of time. They may also be used to investigate the potential use of the intervention in a different condition, or in combination with other therapies."

Source: https://www.australianclinicaltrials.gov.au/what-clinical-trial/phases-clinical-trials