If you remember the 3590 tape drives, you will remember the initialization required. It was unique to each tape drive, and you could format the same tape cartridge for use in different drives, resulting in different capacities (10TB, 20TB, or 30TB). So the tapes were either sold as "plain vanilla" or pre-initialized for a specific tape drive.
With LTO-9 media, the situation is similar. Each LTO-9 tape needs to be calibrated the first time it is used, and that calibration can take anywhere from 15 minutes to 2 hours. Not only does this mean that you have to spend time initializing the tape, but it also means that your host software needs to know that it has to wait until the tape is ready so as not to throw an error. A large portion of your backup window, which is usually a couple of hours, can be spent initializing the tape.
For some people, it may make sense to initialize tapes during production hours. Let us say you initialize the tapes during the day, so you have them ready for backup during your backup window. But even then, you would need to manage 2 sets of tapes - calibrated tapes and non-calibrated tapes.
What we can imagine for the future would be an opportunity to sell pre-calibrated media, and either the integrators (like us) or manufacturers need to take advantage of this by offering pre-calibrated media. Integrators could also start offering this as a service
You can not ignore tapes if you have a comprehensive backup strategy, and migration to LTO-9 is inevitable. The long calibration time is an obstacle that must be removed if adoption is to be accelerated.