> BoFa and JPM Chase, which has both consumer and IB/trading operations can do this in a week.

They can "do it" in the same way everyone on HN can build a Facebook clone in a week: by skipping all the parts that make it hard.

Banks are huge, bureaucratic, political organisations with fifteen layers of CYA and red tape around everything that moves. They couldn't change the favicon on their website in a week if the survival of the human species depended on it -- to build and deploy a product that actually shuttles consumer cash around in the market, you're looking at years of planning alone.

I worked for one of the two banks I mentioned and while it is definitely slow compared to the tech companies, it's not even remotely close to years to ship a product. Things have changed with banks with people more open to MVP's.