But the premise that there will only be 10 launches per year is (hopefully) false.
If launches get much cheaper, there are many reasons to launch more stuff. To orbit, to the moon, to Mars, ...
If launches get much cheaper, there are many reasons to launch more stuff. To orbit, to the moon, to Mars, ...
As it is, that pipeline is fixed at 10 launches per year. If the pipeline were fatter, they could fit more launches into it. If they can do more launches, they can court more customers.
If cost to orbit is cheap enough, you can do things like launch a big, dumb tank of water, xenon, hydrazine, liquid fuel, food supplies, oxygen candles, or anything else useful only in quantity, and requiring no life support. With those up there, you can do rendezvous-and-go missions, and it costs less money to get to wherever you're going. If you can do more launches, you can spread more missions out across multiple launches.
In the end, the rocket is not really the most expensive part. It's just the part that, until recently, was expensive and thrown away after a single use.
Looking at the spaceflight calendar for the rest of the year, there are 6 flights where Ariane 5 could used, if you exclude all the national missions from non-EU countries. Let's round that to 10 as this does not cover all the remaining launches. So we are at a possible market of ~20 launches a year, with the current cheap prices of SpaceX. In order to justify reusability, Arianespace/Airbus would need to plan on having a 90/100% marketshare of the very competitive market, while their US competitors could benefit from quite lucrative military missions.