No, I do understand all that. However, you stated the basis of this change would be to eliminate the use of the USMLE by residency programs to rank students. In order to truly accomplish this, the test will have to be pass/fail. Based on the Step 1 and Step 2 first time pass rates at my school, I can tell you that very very very few people would stress out over the "new" combined test if it were pass/fail (seriously fewer than 3 people out of 200 per class).
If they kept the numerical scoring system but pushed the test until after 3rd year, it would simply force people to take it early in fourth year so that residency programs would look at them. Residency programs would begin requiring or "strongly recommending" that applicants take the Step 1/2 hybrid earlier in order to be ranked. This is already happening with Step 2 and certain residency programs. (I don't know if anyone officially requires it, but I do recall a PD who posts on SDN saying that he gave preference to those who had taken it and scored well, and encouraged applicants to take it in time to have their scores before ROLs were due.)
In summary:
True elimination of standardized test as comparison tool would require pass/fail, and surely sales of materials would plummet
Pushing the test 'til later would just make people take it earlier, sales remain the same, or perhaps a little lower since people tend to freak out less over STep 2.