First off the source isn't the most reliable and unbiased news source, this is the same place I ended up at a few years ago looking for solar and wind generation options for my cabin. They didn't want to offer much advice since I wanted to use evil batteries instead of connecting to the grid to share my generated electricity with everyone else despite my explaining that I would have to cut a path through the trees a mile up the side of a mountain to run electric lines to connect to the grid to share that electricity and which is why I wanted to generate my own in the first place. This also the site who will publish an article on how the energy grid is run at higher than 100% capacity so we all need to conserve more and then turn around and tell how great it will be to charge our electric cars on the extra electricity at night (hint, if we are over 100% already where is the extra). I was labeled something called a repub and told I must watch some news about foxes (I rarely watch tv and even then its a show on netflix with my wife).
(Hope I didn't get too political there, wasn't the intent just showing that the articles there are not that unbiased or well researched).

Laws of thermodynamics come into play, the higher the pressure you compress the air the more power it takes to compress it. More heat is generated, the tank has to be stronger and therefore heaver. Or you could make the tank larger and then sit on top a big tank and of course the larger the tank the heavier it gets.
The power used goes up exponentially so once you scale up from a small tire filler that can run a few hours for 1$ to something that can compress enough air to run a car for a few hours it costs more to run.

Or think about it this way, I have a couple small hand held air tools like a grinder and air ratchet. Both the size of a small drill. My little compressor with a couple gallon tank can run one of those for maybe a minute before it needs to refill.
To make the calculations easy lets say 1 gallon of compressed air would give 1 minute of run time to this little 1/4 HP motor. Now scale up to car size, 50HP motor would need a 200 gallon tank to run 1 minute, 2000 gallons to run 10 minutes, 12000 gallon to run 1 hour unless you start to compress to higher pressure. So you go from 200psi to 400psi so you can regulate it down, now you need a compressor thats eve bigger and consumes more power.


I took steps that I think are even better long term. Instead of living within city limits and driving a hybrid car 5-10 miles each way to work and back I found a place outside the city where my commute to work is .5 miles so I walk when I can. Kids school is 1 miles away so if gas got expensive I could just walk or bike. Even on rainy days my 20mpg truck goes .5 miles compared to the 40mpg hybrid driving 10 miles (or more the average is more like 20). Instead of taking the suggestion of getting a minivan (25mpg) and renting trucks to haul things or having a weekday commuter and a second vehicle for weekend needs I just went with one that can do everything and live close enough to work to not need a vehicle. Sure I'd like to live in the country but until the kids are grown and out of school it works out better to stay close to the school and work and save that way instead of beta testing an unproven technology to let me drive long distances.