What happened when Sanchi was "discovered" in 1818?

Three gateways were standing, and the fourth was fallen

Why did Sanchi's fate differ from Amaravati's? It's possible that Amaravati was found before scholars recognized the value of the discoveries and the necessity of safeguarding them in their original context. The idea of keeping artifacts on-site rather than moving them gained acceptance later. In the case of Sanchi, its "discovery" in 1818 occurred with three out of four gateways intact, and even the fallen fourth gateway remained in place. Despite proposals to transport a gateway to Paris or London, Sanchi's preservation prevailed due to various factors. As a result, Sanchi stands today while the once magnificent mahachaitya at Amaravati is reduced to an inconspicuous mound, stripped of its former grandeur.