B-Trees have stood the test of time for over 50 years, predating modern hardware. They are efficient for data storage, indexing, and synchronization, especially on modern highly parallel hardware. The cache efficiency of B-Trees benefits from hardware developments and allows for seamless scaling. Lock coupling provides fine-grained synchronization, while optimistic lock coupling reduces contention between threads. Despite the availability of other data structures, B-Trees remain practical and efficient for general-purpose performance. They are not becoming obsolete due to their adaptability to modern systems and their ability to handle highly parallel environments with ease.
https://cedardb.com/blog/optimistic_btrees/