This is because Laos is not even self-sufficient in food now, without enough food, then the population is bound to develop.
Maybe when you hear that more than 7 million is not small, but for the size of Laos, such a population is not matched, the overall territory of Laos has 23.68 square kilometers. Such a huge territory is home to 7 million people, and Laos is a country where the population lives in a scattered manner, just like the small villages in China. This is why Laos is still so poor, they have not entered the urbanization, the dispersion of the population will inevitably lead to the dispersion of productive forces, those industries urgently need is a large number of people concentrated together, and the current situation in Laos will inevitably do not meet the conditions of industry.
Laos is a proper agricultural country, then you may think that the country of Laos has a lot of plains suitable for farming, but in fact not. Laos 80% of the country, are mountainous has been covered by forests, and this area of the Lao people have no way to reclaim out for the public, so only in that only 20% of the land for agricultural cultivation, and Laos's level of industry is not good, it is equivalent to the plowing is still in the use of livestock, while other Western countries have long been into the age of machine farming.
For example, Laos's neighbor Cambodia, although Cambodia's land area is not large, but because the whole area is plain, and rely on abundant water, so it is very suitable for the development of agriculture. But Laos is not so lucky, most of the territory of Laos is covered by forests, coupled with the influence of the terrain, that only 20% of the land can not be well utilized, into good land. Therefore, the agriculture in Laos is very backward, and the backwardness of the industrial equipment makes the development of agriculture even worse, and the income level of the people is very low. Laos's agricultural development for nearly 10 years, only to be able to barely realize 77% of farmers to achieve food self-sufficiency, while there are still more than 20% of farmers in Laos do not have enough to eat.
Then you may say that since I can't grow my own food, then import it from foreign countries, which you're overthinking, imports from foreign countries are subject to both tariffs and other miscellaneous taxes, which would have been a big step higher in terms of cost, and for the underdeveloped country of Laos and Europe, it is natural that there is no People can't even have enough to eat, so how can they reproduce? Even if children were born they probably wouldn't be able to feed themselves.