I think the real question is with so many good ideas why not use them?
Because the expense is so great the risks must be mimimized. In the old days the movie process was total integration. From the idea down to the theatre it played in, it was all decided at one place.
This made the whole thing easy to control and budget for.
Now that everyone is a free agent, they are out for themselves. This isn’t a bad thing, but it means COMPROMISE. You’re going to have to modify your vision.
This means by the time it goes from point A to point Z 24 other opinions have effected this vision.
On the other hand it’s unfair to compare a remake of a silent film to one remade with sound, as you’re using additional technology. Similar as if you made a cartoon version of something or a color version of a B&W movie.
Another thing few people noted on was copyright. Hollywood used books and other sources that fell out of copyright into the public domain. This made for some of the greatest movies. With extension of copyright, this means Hollywood today is going to cough up big bucks, JUST to get the rights.
For example in an interview Jane Evanovich, author of the “Stephanie Plum” mystery books, said that the money paid her for the right to make the first of the books into a movie made her financially independent. Sounds like a lot of money, though I don’t know the exact amount. And that was JUST for the first book AND that movie has never been made.
Remakes also offer a chance for a success. Look no one wants to invest in a loser. You NEED something to drive investors (AKA stockholders) to your door. If you have a remake and it makes even a dollar you can say “OK look we had 9 losses, but we did have a winner.”
A remake is a lot easier to predict, as you have a set number that will see it, to compare to the original. A set number of pre-sells to cable and DVD as people who want to compare but not see the original but will in other formats and so forth.
Finally remakes often change over time in opinion.
The 1939 version of “A Christmas Carol” pales in comparison to “Scrooge” the remake in the 50s, but TV heavily promoted the 1939 version, most likely as it was more family oriented and less friendly. “Scrooge” was better but it wasn’t till the mid 70s when it became the “classic” and the 1939 version lost favour as a pale rework of the book.