Their business model isn't about getting people to use the shared bikes for a small fee. It's about getting people to pay the initial deposit for the right to easily use the bikes. There's room for more than 3 bikeshare companies doing this. By creating an oversupply from funds invested in their capital account, the company can create the illusion of having many bikes available. As soon as someone experiences even a minor problem with finding a bike from their current bikeshare company, they may sign up with and pay the deposit to another company. Although a company in theory puts the deposit into a special account and returns it to the customer on demand, in practise they don't if they go bankrupt and the deposits have already been skimmed.
I experienced this trying to sign up with Mobike as a foreigner in China. After taking a 299 rmb deposit from my bank account, their app presented a screen accepting Chinese citizen ID numbers only. I couldn't find a menu option anywhere for retrieving my deposit money. What is the deposit amount for those bikeshare companies in Seattle?
I tried signing up one week ago. Perhaps they've changed since you were there. I used their service in WeChat linked to WeChatPay to sign up and pay the deposit, after which I hit the "enter your ID card number" snag. I also tried downloading the app on their website but it doesn't run on my phone (running Android 4.4.4) which I bought in China.
Edit: I still maintain an integral part of the business model of smaller bikesharing companies is collecting the deposits and using the money for other things.
$0 for Limebike. Your first ride is also free and they’re aggressive with promos (invite someone else, you each get $3 in credit, etc).