Some good points. I might further add a couple of things:
Racing is good for those coaches that constantly overload with intensity/volume because it forces them to cut back and let the athlete recover - so avoiding burnout. The more competition phases the more they have to and the better it seems to work (just as it works for throwers with more cycles in a season). They can only go 10 weeks at most before comps so their athletes don’t get as overtrained.
While comps are good for running fast problems occur when the coach lets their athletes run indoors despite not doing any block work or speed work (e.g. just LDS and fartleck). This is when hamstring injuries etc happen.
This situation isn’t helped by coaches like John Smith saying “we don’t unload for the indoor season”, which while perhaps true doesn’t mean they just add the indoor races to the training program without making any alterations. A similar problem occurs when people like MJ say “Coach Hart gets his athletes ready to run fast from the start of the year onwards and doesn’t taper for competitions” Of course they taper for competitions they just don’t do the normal Long to Short mistake of dropping volume each week.
Double periodisation involves two peaks. In the case of Michelle Perry & Merritt they were both in heavy training & their performances in Australia were a long way from their best. Meritt lost to Steffenson & Michelle got pushed by Sally McLellan. Linford would be 0.3-04 outside his 100m pb when racing in Australia. In the strict sense of the word - double periodisation can’t be used for Meritt, Perry or Linford since none them were anywhere close to their best during Feb-March.
For Australian athletes, double periodisation equates to pitfall results. Racing at your peak during Feb-March will only end up in sub-par performance at major comps.
I do agree that some training methods for sprint coaches in Australia is hard to fathom. I think the problem originates through taking ideas from John Smith, Dan Pfaffs or CF without really understanding the bigger picture. A little bit of Charlie, John & Dan is not the way to go. It’s a coaching generation of copy cats. Individuality of training programs is a dead concept.