^ I'm not so sure about that. Sterling Bay is one of the parties pushing for this behind the scenes, and their contemporary design for
the new Clybourn stop would not look out of place in London or Paris.
Also CDOT seems to be taking the lead on the planning process and all the new CTA stations they've done have also been contemporary, if not always elegant. Remember, Metra usually defers to the local jurisdictions for design of stations. The suburban stations all look old-timey because that's what the suburbs want. Peterson/Ridge is admittedly a stinker, but I think that's partly because CDOT wasn't involved and Metra just gave the design commission to the same guys that design their maintenance sheds.
As for the cost, the Fulton Market station is tied up with a new flyover that will eliminate the A-2 crossing, where all the UP-W trains going to Ogilvie have to cross in front of all trains going into the north side of Union (so MD-N, MD-W, NCS, Hiawatha, Empire Builder). That is an important investment to eliminate a major bottleneck on the system, and honestly worth spending half a billion dollars if it unlocks frequent CTA-like service to O'Hare or along the existing Metra lines.