You have me at a slight disadvantage, as I do not have the the Snell and Vasala schedules. I also don't know if, at this point in their season, they were inside one of these classic phases, or if they were in a "continuation of racing" phase, which just maintains capabilities, without overtraining or overracing.
I recall here, you said that specificity was a missing concept from Lydiard, and this lack of specificity is one thing that separates his outdated method from every modern method. This is the statement I reacted to. I said that it is not missing, that it is included in the COORDINATION phase, specifically with "TIME TRIALS" and "DEVELOPMENT RACES". I further said that this was a key concept that separated his method from "interval trained" runners at the time. In this phase, "TIME TRIALS" are a key tool to help identify and correct weaknesses, not only because it's "self-correcting", but also by signaling how to change your training (i.e. with under or over distance racing).
I agree that the Lydiard "MARATHON CONDITIONING" and "HILL" phases are generic. The same for 800m to marathon. The "ANAEROBIC TRAINING" phase is customized for the athletes event, but I think it's still not SPECIFIC, the way you mean it. It's the training that comes *AFTER* the "ANAEROBIC TRAINING", that, I say, incorporates SPECIFIC training. So maybe 18 weeks are not specific, but then the last 6 weeks include specific training.
I don't want to argue what you mean by SPECIFIC, or if Lydiard is SPECIFIC like Renato, but hereafter I take it for granted that running race distance at near race pace (e.g. Lydiard's 3/4th effort, or 7/8th effort), qualifies as SPECIFIC training.
As you know, books are important for me. I don't have Snell's or Vasala's schedules, but I do have dusty 1962 copy of "Run to the Top". The chapter, "Building in Speed", comes right after our "learner" has completed the marathon training, and hill phases. What follows is 12 weeks of training at the track. These are the last 12 weeks of training before "THE RACE". Although not named here, these 12 weeks correspond to a 6 week "Anaerobic Training" phase, followed by a 6 week "Coordination+Taper" phase. He says, "Primarily, this first six weeks on the track primes the athlete for the RACES that lie ahead in the next six weeks." I interpret this to mean that the first 6 weeks, although customized for the athlete's event, could still be highly "non-specific". I have no issue with that. It's during the last 6 weeks, before "THE RACE", that Lydiard training includes "SPECIFIC" training: time trials and real races.
So, even though I earlier said I never looked at the schedules, let's take a quick look at schedules he published worldwide for me and the rest of the world in 1962. A couple chapters later, in "The Schedules", Lydiard includes customized 12 week schedules for 880 yds, 1 mile, 2 miles, 3 miles, 6 miles, and the marathon, as well as 3 1/8 mile and 6 1/4 mile cross-country. In all of the 12 week schedules, there are plenty of examples of time trials at race distance, and racing at half distance or double distance.
For the 880yd runner, the third week of month 2, on Tuesday, we find "This is the first of your time trials...". Full distance time trials are run for that week, and the next 3 weeks. Also mile races, 440yd races, and one 880yd race, before tapering for "THE RACE".
The other schedules (except the marathon) follow a similar pattern, with at least two time trials + races each week, in the last 6 weeks of training. The marathon has been supported all along by the initial marathon training, then the long runs. The marathon schedule doesn't include any full distance or double distance time trials, but interestingly includes one marathon race 3 weeks before "THE RACE".
The way I learned it, incorporating specific training, i.e. the full distance time trials, with over distance and under distance races, was a key factor in upsetting the "interval trained" runners at the time. There is a famous story about Murray Halberg creating a huge gap in the last 3 laps of a 6 mile (10K?) race, because all the other "interval trained" athletes wanted to stop and rest. Halberg created a 70-80 yd gap in one lap, because he was trained to race the whole way.