At least natural gas had distribution already (but usually not anywhere near the pressure needed for fueling; and that compression is energy intensive!). The pressure tanks in the vehicle expire, at which point the vehicle turns into a pumpkin. At least early Mirais had 15 year tanks.
In theory, you can replace the pressure tanks, but when I was looking at aging CNG Crown Victorias (circa 2017), it was very hard to find new tanks (and many of them had been sitting for some time, so you're not even getting the full tank lifetime), or someone to install them. When I saw cost estimates, it was in the couple of thousands; not really economical when that money would get you a similar age gas car that will probably never need its gas tank replaced.