They may save on average, but that's just shifting the expense to the customer in terms of wasted time. If there is anything I've learned over 30 years of running businesses that being disrespectful towards your customers' time it is that you will end up losing those customers.

The saving grace for these online services seems to basically just be that the potential customer base is so ridiculously huge that it still pays vs effort required. Same for the big social giants etc.

No matter how many people know better, there are plenty more that don't.

Another way they save is by discouraging their use. Since people who've called with real issues have had to waste a whole lot of their time, they're more reluctant to do so the next time they have a problem.