And if you admit passengers favour direct flight rather than flight with tech-stop or stopover, I think Sami should have some algorithm to reward those direct flight. That reflects in RL some operators tends to order planes with longer range to serve direct flight, and the reason why B744 used a lot in Cross-pacific route because they need not stopover at Anchorage.
If the effect of frequency is reduced, all the variables that are already there will have more of an effect. Even in situation where 2 airlines have 1 flight each. One direct, one with a tech stop. If frequency accounts for, say 75% of competitive value of the flight, and each airline have frequency of 1. both of these flights are 75% the same. Now when you take into account that there are number of other variables, let's say 5 other variables in total, each accounting for 5% of competitive value, flight time being only 1 of the 5, then the these direct and indirect flights are 95% the same. The 5% they differ in, the direct flight may be 10% faster, so we are down to .5% difference.
Now, if frequency was not such an overwhelming influence, all the other variables would become more significant.
As far as passengers favoring direct flight, a lot of LH leisure passengers overwhelmingly prefer cheaper flight, and are willing to transfer between flights, wait 3+ hours for their connecting flights. A tech stop in comparison is far less hassle compared to that. And as we know, cheaper price does not amount to very much in AWS.