Extend Threshold Work over longer period in workout?

Hey guys,

I wanted to ask a question which I could not find a satisfying answer to online

So the question is:
What happens if you extend Threshold Training over a longer period of total time with longer rest periods and WHY would you do this?
Some say it helps to improve “aerobic power” etc – which is a bit of a general statement.

Example:
5 minutes @threshold pace – 5 minutes recovery run x 6 sets (increasing 1 minute per week for progression)
VS
5 minutes @threshold pace – 2 minutes recovery run x 6 sets (increasing 1 minute per week for progression)

Most people describe threshold work with 2:1 up to 4:1 rest periods BUT for example Renato Canova uses the 5/5min x 5 (adding 1 minute to the work portion per week) very regular. What is the up side of this? Do you guys use this and why/when?

Does this mimic a more specific fatigue related to long distance running? iE. Marathin/Ultra Training if you spread it out on a 2h workout for example? Would you describe sessions like that more for fast twitch athletes to have. a longer recovery period to allow better shuttling etc?

Sorry, a lot of questions, hope I can get an answer to some of those!!

Thank you in advance

Best Regards
Florian