The EV market is in state of flux at the moment. Before Dec 2016, there was ONE company selling a 200+ mile range EV, and it cost well over $65K, AND it had it's own private charging network. There are now two new sub-$38K 200+ mile range vehicles (although less than 20K sold so far, world-wide) being offered, and another one (the LEAF2) is around 160m now and more later. (I include the model 3 because free supercharging isn't built in to the base price - so the new stations that can fast-charge teslas will get some Tesla use as well). There are also *announcements* from other vendors (and suspicions that the Ioniq EV will soon have a greatly expanded range, up from 120m).
For the 'installed base' of non-Tesla EVs, most are around 80 mile range. I mention the 80-mile and 200-mile issue because a DCFC for an 80 mile car will probably take 15-25 minutes to fill the battery to 80% or beyond. So places that wish customers to stay longer than (say) 25 minutes aren't going to get much extra business from a 50 kW DCFC - the 'customers' will just sit outside until the charge is done, and leave. For those wishing to be in the business of being "EV stations" (compared to gas stations), well the lower-range EVs generally stay fairly close to home (I am an exception, but more on that later). You have to be a little eco-wacky to take your 80-mile EV on a 260 mile trip. So the tens of 1000s of EVs already out there charge mostly at home or work.
What is the incentive to install something that won't bring in customers, that will often be sitting idle because you have to charge too much to earn back the costs? NOT MUCH. Why would a person pay 2 or 3 times what electricity costs at home if he didn't need to? EVgo is handling it (sort of) by charging monthly fees, getting those who can't easily charge at home to pay that, then boning them on the charge prices when they do use the DCFC. Say, apartment dwellers. They also partnered with a "eco friendly, tree-hugging company" (Whole Foods) to install chargers at many of their locations AND are getting Nissan (and others) to pay them for the "no charge to charge" plan. The customer doesn't pay, so they use it as much as possible, and the car company pays instead. A nice revenue stream. There is also the "company perk" situation at the moment (at least where I live). There are many, many, many companies the the SF Bay region who provide free charging to employees, and a few that offer DCFC spots for free as well.
So, now things are changing. The more 200+ mile EVs are driving around, the more profitable the DCFCs become. For highway travel, the fastest, most reliable, most convenient DCFCs will get the most business from travelers. A car that will be plugged in for an hour (or more) is more interesting for businesses that want to get EV customers in the door. Restaurants and malls (especially those close to freeway access) suddenly see an interest in having a DCFC (or two) on premises. "EV stations" close to freeways are used more, and thus more profitable (especially those in "dead areas" where there aren't any other DCFCs for 50 miles). If your restaurant is the only one with a DCFC for 50 miles, you will probably get most of the EV business around 11:30-2, and 5-8p.m.
So, a year or two from now it *should* be more profitable to have a fast charger - there will be 10s of 1000s (or maybe even 100s of 1000s) more longer-ranged EV on the market, who will be likely to use your service.
Comment 1: a 24 kW DCFC can be highly useful for many businesses in an urban setting TODAY, since a 80-mile EV car might be there for 25-50 minutes. So restaurants and grocery stores and department stores can get the "EV business" if they are one of the few that offer that in the area. The cost for a 24 kW charger is also a lot less. There are Walgreens stores here with 20-ish kW chargers in their lot. Since the lower powered DCFCs wasn't the subject here I didn't bing it up in my initial ramble.
Comment 2: earlier I said "the lower-range EVs generally stay fairly close to home (I am an exception, but more on that later)". Where I live, I have a LARGE number of non-EVgo DCFCs available (well over 20 between SF and my house). Most of them are less than 5 minutes off the freeway. So I don't mind doing a 130-mile round-trip to SF and stopping at a DCFC for 20 minutes to fill up. I do a "well over range" trip at least once a month, and often more than twice. Heck, NASA just installed a a DCFC complex
DCFCs, near the junction of two major freeways. I'm spoiled.