Time&Temperature vs energy needed for molecules structure's changes
The hypothesis is somewhat valid. The version which is true is: there is a correlation between the total amount of energy which went into the meat and the degree of doneness. And because the total energy is the rate of energy input multiplied by the time you are adding energy to the system, time and heat are interchangeable to some extent. 

However, there is no constant "total amount of energy" which needs to go into the meat. Protein denaturing is a complicated stochastic process. If we were to assume that we have a uniform thin layer of meat and a perfectly uniform heat source parallel to it, we still wouldn't have a constant total amount of energy. It is a bit less noticeable with meat, where preparation methods are limited (*), but in eggs it is easy to observe that the speed at which yolks are heated will have a noticeable difference on the final texture of a custard. 

Even if you could get away with a usable range for the "total amount of energy", you could still not predict the time needed by a given piece of meat at a given temperature. We are talking about a complex nonlinear system here. That part is a duplicate of another question, so I will simply post a link to my older answer. 

So in the end, there is a very good reason why you should check for doneness instead of try to predict doneness. Or, in the special case of sous vide, use the empirically determined charts somebody else went to all the trouble compiling. Calculating it for yourself is completely impractical.