Re: "using cheaper-than-plane airships"
"The $40 million Airlander 10 is not believed to have any passenger facilities at all."
Neither does a 747-F
"A developed production version due in 2018 is touted as having 19 seats."
Which is about 12 more than I was expecting to see in a machine designed to be a cargo lifter for awkward or bulky items and/or areas with difficult access.
Passengers would get bored quickly. Put them on aeroplanes.
"Maintenance costs are enormous for airships and far outweigh the fuel costs. And they have to be tended all the time while parked on the ground."
Funnily enough the same applies to GA aircraft and - more to the point - to helicoptors.
Which is where we get to the point of them. These birds aren't competing with fixed wing aircraft. The competition is heavy lift helicoptors which are both extremely thirsty and limited in capacity (The biggest Sikorsky Skycrane can lift about 10 tons but it's only got a range of a few hundred miles at best while carry such loads)
There are also applications for carrying heavy/awkward cargo such as refinery crackers where roads aren't up to the task - these kinds of loads need upwards of 100 wheels, travel at 2-3mph, take the entire width of the road and by necessity are limited in their manouverability, and as such the expense of an airlander is justified (in the same way that an AN125 or 225 is justified for certain types of extremely large/heavy cargo even if the delivery flight cost might exceed that of the actual equipment.)