Ayurveda is a science, no doubt about that. But it has been disrupted for quite too long, especially after the takeover by the British. This question is a good background to discuss the historical background of the fight for supremacy between Ayurveda and Allopathy.
After gaining political supremacy in India, the British started to install institutions that were beneficial and supportive of their dominance. They dismantled the indigenous education system of India (Gurukula) and outlawed the practice of Ayurveda. Without political power and shifting economical power, Ayurveda and many other indigenous institutions lost their relevance. This is how Ayurveda was uprooted from the land of its birth.
Falling out of support, Ayurveda lost its patrons and due to persecution by the state, it lost all its significance. Practitioners of Ayurveda, at times, were treated like criminals. So it was easier to study and practice Western medicine than Ayurveda. Without systemic support and persecution, there wasn’t much research conducted in Ayurvedic fields and hence there was no major text written during that period.