No long runs for IM training?

More is more.

I think higher mileage is a better bet. The more I train, the faster I race.

The recovery from a long run is not worth it for me.   But I just wonder if the long run will teach the body to run longer distance without breaking down.    Its amazing...I can run 12-13 miles not problem but the minute I go over 16 miles I need rocovery.

Is it that you "feel" that you will have a harder time recovering and "feel" that you are more injury prone or that you "do" have a harder time recovering and "are" more injury prone.  Because if the former, then slowly going from 12-13 mile long runs to 13-14 mile long runs to 14-15 mile long runs will acclimate the body.  But if the latter, than you can try increasing the volume per week without increasing the long run.  Your body will get used to greater volume, which will help in tackling the marathon.  Just you should at least do greater than 12-13 mile long runs every once in a while to get used to the mental and physical battle of a marathon.

As for your friend who does 70 miles/week, 10 miles a day (assuming that's sometimes 10 miles per run rather than a sum of different runs that total 10 miles) is a long run in the majority of people's eyes.  And I'm with the other poster, genetics are a great thing.  Plus, how long has he been doing that?  If he's been doing that for 10 years already, his endurance and aerobic capacity are part of the reason he can do 2:40 marathons.

Why not slowly build up to 16 miles?  Going from 12/13 mile runs to 16 is actually a big jump instead of 12/13 to 14.  What about increasing volume per week without increasing the distance per long run?  The added volume in time will help to run longer single runs eventually.

Many coaches and plans have limits of 2-2.5 hour long runs depending on individual in IM training as the risk of injury and recovery is to great in longer.

I don't know many folks run 50-60 mpw for their first IM.

Training  and racing an IM Marathon is quite different than training and racing for a stand alone Marathon.

This. More running will probably make you faster, but you aren't just running during your IM. You need to be sufficiently recovered from your long run to swim and bike the next day.

It's cost/ benefit. You need to spend enough time training in all three disciplines. Running 50 mpw doesn't allow for a lot of time to do much else.

Your post doesn't reflect on why you crack at 16 miles. If you haven't already considered this question, then I would do so. You can be pretty sloppy with your drinking and eating on a 13 mile run and still be fine. As you go longer, it becomes more important that you have a careful nutrition plan. I feel this is true both in terms of performance during the particular run or race, and also in terms of recovery. Ironman is all about finding an effort zone and a nutrition plan that lets you go on and on and on. If you can run 50-60 miles a week, then maybe I'm off base, but I thought I'd mention it.