Base training -> quality aerobic training -> lactate threshold training -> VO2 intervals -> taper, race fast -> REPEAT
It seems like a lot of recreational runners dont really have a lot of periodization in their training. Like you said, people run the same 3 types of workouts week after week, and I do think your body gets a little bit stagnant. I think the solution to this is training in phases, or period. Each period has a goal, and it progresses you towards the next period. This is the classic lydiard pyramid paradigm, first lay down lots of basework before you sharpen that off with speed. If your training is getting a little bit stagnant, watch out, you could be overtraining and you could be close to a crash. This would be a good time to back off in volume and distance. take some time off, regroup, let your body really relax and "detrain". Then take a while to just run easy mileage before you build up to longer aerobic effort-based tempos and fartleks before you finally polish things off with 1-2 months of VO2 max type intervals. Taper, crush our goal race, and then take time off.
Runners these days just bounce from race to race, not following a season plan (macrocycle). Ya gotta pick the goal race, then progress up to it. the first 3rd of your cycle should be easy. The middle 3rd should be "normal", and the last 3rd should be more intense than you could maintain indefinitely.
Another idea is to look for some different training. I know a guy who trains 100mpw+ for the the marathon and he does the same thing every week, all year long. He just keeps throwing down these nasty marathon type long runs and long lactate threshold sessions. The dude has been doing this for years, and as you might expect, he hasnt progressed very much. I thin he would be better off doing a marathon cycle, but then doing something reall different like a 10k cycle. Take some time to work on different skills, run some faster intervals, get more comfortable at a faster pace, and then take those skills back to another marathon cycle. I guess the thing im trying to say is that VARIATION is the name of the game. Ya gotta keep throwing something slightly different at our body, so it continualy perceives your training as novel stimuli that it must super compensate for.