I don´t think so. I think that what you say is an absurd somehow.
First of all, your example is not correct. 3k pace workout is specific for 3k run event but IT´S NOT for a 10k run for a 10k event. 3k pace for a 10k run it´s not specific it´s special, because it´s too distance from 3k race pace target event. Specific is everything paced exactly on race pace or 98-97% or 102-105%. This is yout first mistake of specific workout interpretation, one misunderstand.
Second it´s completly false that if you need longer lenght interval the workout lenght it´s too dificult or shall be avoid. Dificult ? What´s too dificult ? I might agree. But do you want to run progress with easy workouts, without difficult workouts ? You willn´t get there. You need not hard or easy workouts, you need rich workouts, adequate workouts relate to the training need.
As i tried to to justify it´s true that if the specific workout is in the training zone fater than vVO2max, - then with high percent of anaerobic effort, you need more than 1:1 ratio. That are all 800m, 1500m/mile and 3000m SPECIFIC interval workouts.
Since that the lactate is very high if you run for a longer distance in your 800-1500/mile pace, you need a long recovery of many minutes, longer lenght than every interval set.
Imagine that you run this wokout. 6X600m at 800m race pace to prepare a 800m run. Afeter the second of the third set your are in high lactate. It´s impossible to run this workout without longer recover than 1:1 ratio.
I give you one real example. Do you know who was Fermin Cacho, 1500m olympic winner, eurpean champion, sub 3:30. His coach used to run one late interval session to test him for 1500m. The workout consists in 3X1000m at Cacho´s 1500m pace. Very fast indeed and very long, each set long, and the total workout 3000m very long because exceeds to 1500m run distance, but one very good workout, top of the specific. Do you know how lenght recovery needed Fermin Cacho, how much time his coach give him between each 1000m set. 11 minutes of walk recovery that he is able to complte this very difficult workout, but a good specific one.
Do you want to know how many time Rui Silva used to do in between 2X1000m+1X500m+1X300m, that is a 1500m specific workout ? 8 minutes of recovery.
Do you want to let me know that they can be more productives with 1:1 ratio that what they were with long ratio recovery ?
In both cases, Rui and Cacho eventually they were best runners than Marius Bakken whatever. Rui did run several times against Marius in 1500m as well as 3000m flat ansd he did win everytime. Rui confesses me that Marius couldn´t win over him never. This remembers me Carlos Lopes when in 1984 before LA olympic marathon they ask him: Don´t you fear Alberto Salazar, he is so strong and he run in his country. Do you think that i ever let Salazar beat me in US ? I don´t. He didn´t really.
You can use the intreval it pleases you, but i tried to argue why in this specific long race pace intervals, why longer recovery lenght intervals is more productive, it´s because anaerobics. You couldn´t say why short recovery lenght is more productive. You just say can be done, ok let´s admit that can be done with short recovery buit what´s the benefit to do 1:1 than 2:3 or 1:2 whatever ?