It's All Down To Cellco Attitude!
In Indochina, political history plays a big part in most things today.
VietNam acts like an adoptive parent to Laos (VN also supplies International InterNet access to this country), VN dislikes Cambodia and hates China. (No Chinese programming is permitted on any VN medium)
Laos and Cambodia are fine, and China is acting like a sugar-daddy millionaire to both of them, 'giving' them the latest Chinese-made network equipment
Back in the day, after VN had backed out of Cambodia with it's army, it donated base TV station transmitters to both Laos and Cambodia. VTV (VN) is on one of the channels in every donated system.
VN has handed much of it's used cell base equipment to Laos, as VN cellco's constantly upgraded, Viettel, owned by the VN military, has huge fibre optic installations in Cambodia along with extensive cell coverage.
Within VN there is a network of 5-7 cellco operators owned by either the government of private investors. Whilst they compete for customers, the technical cooperation is surprisingly friendly with well-funded government companies often helping their lesser endowed competitors with back-bone access.
Technically, VNPT (government) is hand-in-glove with Mobiphone (lately a subsidiary of VNPT), but I detect that isolated 'pockets' of coverage, in the more remote areas, by other networks are hosted on VNPT equipment which essentially covers the country,
Viettel led the way with 4G - concentrated around Ha Noi (capital) whereas VNPT hung back a little but when it's 4G when live, so did it's 'competitors'.
Likewise with cable companies - they each help the other. I had access to a major cable company's feed (they 'borrowed' space in one of our underground cable ducts, and using a spectrum analyser found that programming for other 'competitors' was also carried on their networks although filters stopped the average subscriber from seeing what was going on.
There is minimal government intrusion in these arrangements, little coerced cooperation, which demonstrates when carriers get a mature management, with the right attitude, everyone can have a WIN-WIN situation.