It's own voters and Legislative Yuan have been very schizophrenic in defense investments. For campaign reasons and to promote other industries they tend to go with large projects like fighter jets, warships, and most recently a submarine. They also don't want to invest because money on defense takes money away from social programs. Mandatory military service became synonymous with Taiwan's dictatorship so voters abolished it. Low pay and under investments make it a poor career option. Lastly, the Mainland has successfully pressured democratic governments over many decades to refrain from selling Taiwan defense materials, weapons, planes, and warships.