Was thumbing through my BoateUS magazine and seeing more boats advertised with 3 or even 4 main outboards on them. Granted, 2 delivers a safety factor, docking steering control, plus more power, but some of the boat size/length appears to not need it. Any advantages other than a thinner wallet?

Because they don't make 900 or 1,200 HP outboards.

No other way to get to the HP range you want without going to more of them. You don't see four 50hp motors trying to get 200.

Speed & performance is the reason and the rapid growth of center console offshore boats which are up to 53 ft and go like a bat out of hell and are fishing machines.

http://www.seahunterboats.com/
http://www.hydrasports.com/
http://www.evergladesboats.com/
https://www.seaveeboats.com/

The larger 300 / 350 outboards reliability & performance has reached a rather high standard with the ultimate being Seven Marine http://www.boatingmag.com/seven-marines-627-hp-firebreather

557 hp is an option. Check these out.
http://www.seven-marine.com/technology/

Price, availability, parts, lack dealers, etc, probably holds the sales back significantly. In all my years of being in the Keys and other locations I can't recal ever seeing one (or more) on a boat, even though they've been around for years.

I would still like to have to, or maybe 3.

Yet somehow, they are still in business.

Also most multi engine offshore boats have a joy stick control coupled with the bow thruster for handling. Works the same as Penta's IPS or Mercs pods which is another step up. But hit the Seavee link and they have a one pod diesel 39 ft that uses that system also.

The traditional big battle wagons such as Hatteras or Viking ( let alone Jarret Bay / Spencer / Bayliss ) for offshore are in the millions range. You can do a center console for much less be it a 100k income is missing three zeros needed to afford one.

Because you can run a 42' Yellowfin or Contender like a raped ape in moderate seas. That's why. Too bad Washington's weather is so crappy, cold and wet.

This is a Intrepid 475 Panacea with quad 7 / 557's on a run. Money & balls!

https://www.youtube.com/watch?v=o6ILiJQ3fgY

Good hole shot but 200 GPH fuel use is a little steep.

That's nothing. You'd recoup the costs with one run to the keys.