While I have a -ve view of Mill, I do think Max Mueller’s achievement cannot be understated. Contrary to many H internet activists contemporary H leaders took a positive view of him. See here. More generally, I do hold that there is something I term tattvAveSha
To illustrate this imagine an applied mathematician who not ever having seen a planet can predict its existence or a theoretical biologist who without having seen an organism can predict intimate aspects of its biology from its genome sequence that were unknown to a naturalist who has spent a lifetime studying it. Likewise, for a textual culture, if the texts are extensive enough and the knowledge in them presented systematically enough, a good philologist can penetrate the producing culture without ever being embedded in it. As in the above linked note - Jan Gonda from Holland is a good example. Of course there will be lacunae from the lack of being an insider or firsthand observer; however, that doesn’t imply that know insights can be provided by observer from his armchair.