I will hardly say that Vietnam was bogged down in an insurgency in Cambodia see how they pulled on their timetable leaving a government that is still existing to this day.
And trade did still happen between Vietnam and the rest of Asia but it was definitely not on the level of today's.
Vietnam had 180,000 soldiers occupying Cambodia.
If you have a 11 year occupation, it is accurate to say Vietnam was bogged down in an insurgency.
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You also say that the Cambodian government still exists today.
But after the Vietnamese soldiers left, Cambodia was able to pivot towards China, because they do have 2 much larger land neighbours (Vietnam and Thailand)
Now Cambodia looks more like a Chinese client state, which is allowing the construction of Chinese naval and air bases.
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As per the 1990 CIA Factbook, Vietnam's 2 largest trading partners were a distant USSR and Eastern Europe.
That makes absolutely no sense, unless Vietnam is cutoff from trade with its neighbours (China, ASEAN) and also the West.
That is what happens when you have awful political/economic relations with China, ASEAN and the West.
Even North Korea (which had good relations with China and the USSR) was doing twice as much trade in 1990 than Vietnam was.