The answer to this question is simpler than you would imagine.
First pharmaceutical companies are not yet interested in stem cell therapy especially when it is personalized. Imagine you are a pharmaceutical company and you have a pill you can mass produce and ready to be sold sell all around the world. It is a great business model and that is way these pharmaceutical companies have earned a lot of money. However, in the last view years these pills that can be mass produced reached a ceiling. Age relate diseases are simple not curable with a pill. Until today we still do not have a long-term vaccine against the flu let lone covid 19. So how are we going to cure these kinds of conditions.
Second drug approval entities like the FDA need to be assured that a drug or therapy is save. That is, it. But what they mean is it needs to be saved for everyone who has the condition or disease. Because just like pharmaceutical companies (what a coincidence) they hold this dogma that only if it is save for everyone it can be approved. On top of that the 1992 prescription drug user fees act leaves room for agencies and Pharmaceutical companies to close ties which is a disadvantage for clinical trial using stem cell therapy. These close ties and dogmas hold stem cell therapy on a stand still. But what if we would decide to leave this dogma and look for something else.
Simple let go of the old believes that we need one pill that can be administered to a whole population. That model is just pasee and entities who are not willing to let that go are doomed.
What if we look to drug approval in a different way? For example, when a patient comes into a clinic, the whole DNA get sequenced and a proteomic analysis performed. These data can be introduced to AI so it can be compiled to give a better answer to whether it is safe to take the therapy/drug or not.
The more clinical trials, DNA/protein analysis, the better the predictions about side effects become and the more a patient can benefit from a therapy or drug. Accepting this dogma will cost a lot of effort and investments but on the long run it seems inevitable.