I would argue that dropping and creating indexes is much less work than refactoring large parts of your codebase just to change a data structure. Also, you can

I would argue that dropping and creating indexes is much less work than refactoring large parts of your codebase just to change a data structure. Also, you can have multiple indexes on a table and the RDBMS ensures that they are always synchronized, which is something you won't achieve if you code the data structures yourself.