The problem is not only with commercial language companies; only a handful of universities concern themselves with these languages. Their texts are expensive and academically oriented. They are physically removed from the region. Within Southeast Asia itself, not a single university teaches all of the major languages of the region.
This current state of affairs is likely to remain the same for the foreseeable future. The bright side of this is that there is opportunity for anyone who wants to produce and sell quality texts, courses, and other online material for these languages and isn't concerned about making money. Indeed, nearly all high quality Southeast Asian language material on the market today has been produced by individuals, rather than commercial language companies or universities.