The Federal Highway Administration conducts Accelerated Construction Technology Transfer study sessions. Back in March of 2004 the FHA hosted one of these in Seattle where it appears all of the "decisions" regarding the configuration of the 520 replacement bridge were made. Yes, even before much of anything was know of the soil conditions, one of the key WSDOT misinformation points, the construction industry decided a floating bridge structure was in their best interests. Design and construction of a real bridge would require outside experts and WSDOT knows how to build a 50 year pontoon bridge.
There are some really good points brought up. For example replacing (not eliminating) the Montlake Flyer stop with a true intermodal station at Husky Stadium. The idea being that this would eliminate (not reduce) the need for buses crossing 520 to go downtown. They also recommend consolidating all eastside flyer stops between I-405 and the water to one at Belleview way. Of course that would be a "hardship" for the dozens of people that access the flyer stops at Evergreen Point and Yarrow Point. Worse yet, it might eliminate State funding for lids over the freeway at those "Points".