Account connection services are insanely expensive and you don't want to create all that yourself. That would be even more expensive to maintain. That's why there's services like Plaid. For every user it costs at least 1$ a month per user per connected account. That alone creates a huge amount of ongoing expenses.
That's why we don't offer the ability to connect accounts within our app. Users don't understand or don't want to understand that such a feature alone would easily double the subscription price. Without VC you cannot give users the ability to connect their accounts for free without losing lots of money.
I work at Plaid and I think that pricing info is a bit off — assuming we’re talking about just the APIs for transactions data (which is what the budgeting apps typically use) and these prices are in USD, even customers who don’t qualify for any volume discounts are paying closer to 30-45 cents per month per connected account. (Volume discounts then can start to kick in starting at a total API spend of $300 / month -- the higher the monthly API spend, the greater the discount percentage.)
I work at Plaid. The basic, non-discounted rate for the Transactions API is like 30 cents per connected account per month (or 45 cents per month if you're buying some optional add-ons to go with it), and any customer the size of Intuit would definitely be getting some kind of huge volume discount. I can't speak for other companies in this space, but I assume they have similar pricing.
That's why we don't offer the ability to connect accounts within our app. Users don't understand or don't want to understand that such a feature alone would easily double the subscription price. Without VC you cannot give users the ability to connect their accounts for free without losing lots of money.