This is a sad but not unusual story in Laos. It is not even a long story. Years ago, Laos was the host of the ASEAN Games. Since it was lacking the necessary infrastructure, it got loans and support from other countries and constructed the SEA Games facilities outside town. We know from the Olympic Games that these facilities sometimes aren't used much anymore once the events is over.
But for Laos it could have been a different story, because that was the first time ever they had a proper swimming stadium etc.. Now, only the National Stadium is occasionally used for football games and propaganda events. Usually, it is closed. and of course, nobody maintains anything. It is just rotting, plants take over, two more years and wildlife will be populating it (could be just a different use, unintended).
This happens to nearly everything Laos gets paid from other country. Lao authorities don't maintain anything, they let it run down and then ask for a new one. And donor countries are stupid enough to listen.