lost in Boston
namely the flux of talent away from the track and to the roads. why? $$$$$
The best track runners do not go to the marathon for a good reason - and it is also money. If you are the best on the track you make a pile of money.
Do you think these 2.04 marathoners - most of whom do not win the major marathons - could win the 1500 or the 5000 or the 10,000? Of course not.
The fact is, the dopers are a bit more reticent than they were in the 90's and early to mid 2000s. Things are getting a little tighter. The Olympics showed that. (With the glaring exception of the US women sprinters. Puhleazze.)