When i was recently in austria, i saw many of these caged in sports areas. at first glance, you would think they were basketball courts, but instead they were concrete soccer "cages". Maybe some of them had basketball nets. i didn't really pay too much attention.
Here there are 3 kinds of extended ways of playing soccer and types of courts. This is how we call em.
-The most popular to watch but not to play is Futbol 11 (11 players). Thats what Real, Manchester, etc.. play. What it can be called "universal soccer". It can be played in sand or grass. There are few of these fields around and they are always private.
-Then theres Futbol 7. 7 players in in smaller sand/artificial grass field. This is played more frecuently. You usually have to pay to play on this ones.
-And then theres the most frecuent style of soccer wich 90% of people play. We call it "Futbol Sala". Its 5 on 5 played on a basketball size court on concrete or wood. Most of them are public and there a lot around. They look exactly like cages, like you said Fancy.
I have played in this leagues for years.
The anser to this is easy. Big fields are expensive to build and maintain. What you will find in europe in many places will be a "futbol sala" and a basketball court together. Many will be public and some dont. The good ones you will have to pay.