Sub elite but can't handle long runs

Do some longer runs at 140 bpm. You don't need to hammer your long runs if you're not doing a marathon. Then once you can run 3 hrs at 140bpm comfortably, 2 hours at 165bpm won't be so bad

2 hrs? You probably dont need runs that long.

It means you should keep to a HR of about 140 and go easy.

Pro tip: there's no such thing as sub-elite. Elite is a binary status, either you are or you aren't.

Is it strictly that they don't go well or that you're finding you actually need to build in recovery for them? I think ~2 good workouts/week is a sweet spot for most runners. If you do sessions on Tuesday, Friday, and then hammer on Sunday, and you feel like trash for several days, as you try to workout again on Tuesday/Friday the next week, then it does make sense -- you'd be doing too much.

If you're building harder long runs into a training plan, do your weekly session on Wednesday & then treat your long run day as a hard session, with at least 2 easy runs following it.

If you're already doing that then, yes, something else might be at play. Sleep, nutrition, in-run fueling, etc. But it's not a bad idea to do some easy long runs and throw in a mid-week medium long run to build up some stamina. You're not doomed for the longer stuff. You have fast enough PBs to OTQ. You just need to train like a marathoner if/when that time comes.

I'm not nearly as fast as you but had this experience before. Have you ever tried to bring fuel on these 2 hour runs? I noticed that when I ate something like a gel or half clif bar, I felt dramatically less fatigued.

What does reasonable pace mean? Could be that you're just pushing a bit too fast. I think at most I probably do 10 miles @ MP(2:28 pace) and the rest are fairly easy (6:45's to 7:30 depending on the day. If you're in a particularly hot or humid environment you probably need to slow it down a bit and hydrate/fuel a bit more. I never fueled when I was in college but definitely do now, especially when runs go longer than 90 minutes.

just keep hammering your 2 hr runs until they get easier brah

90 minutes is plenty long enough. You don't really need long runs unless you're training for a marathon.

And if it's hot and/or humid, you might be better off with 60 minutes.

No

First mistake is assuming you need 2 hour runs to progress

Running fast and running slow are almost different sports

Try 90’ instead at ~ 1.2x your jog speed in mph

Effort = light to somewhat hard

Keep the long runs at 140 bpm. Eventually that will begin to feel too easy. Then run them at 145 BPM, and so on. Its normal to feel wrecked when you run long runs too fast.

I understand sub elite as meaning a tier below

Then you've got the triers and hobby joggers and turkey trotters

Is there other terms in use for these levels

Non-elite encompasses all those who aren’t elite, that IS the tier below. There’s no meaningful reason to delineate further.