Dive Computer technology will depend a great deal on the advancements in other fields such as batteries, mobile phones, medical technology advances, etc. and thus the cost of research is spread over many other industries. I don't see the use of external noninvasive probes as far fetched possibility. The only work that has to be done by the dive industry is how to formulate these variables into an algorithm that can actually track what is happening the body tissue better than what we have today. 15 - 20 years from now is probably enough time to figure it out and have $$ for it by the dive industry. I am optimistic.