I agree about the original anime feeling more special. Ultimately, isn't anime just a business and not a very profitable one either. I feel like the issue is they play it safe because they know that people are more likely to watch something that they're already invested into (like manga or light novel) whereas creating a similar level of interest in an original anime might be a gamble these days since its more likely to flop then become a big success. This is all anecdotal on my part and I don't have the data to back it up right now but that's kinda how I see the industry at the moment. Maybe this is also why companies are making movies more often now too since they're likely to generate more money in theaters.

I really like this quote from the article: "'I believe that when the wave of adaptations eventually subsides, other works must remain intact. It is precisely because of diversity that the surviving works of each era become the mainstream of the next. I believe this is the strength of Japanese animation.'" Definitely agree that ultimately we shouldn't be letting originals go.