Industry-grade tape drives and tapes are of high quality and usually have very quick data access rates, it's the consumer-grade/cheap stuff that sucks like hell, like DAT for example. What's more, storing backups on tape should be just one element of your backup strategy. Tape backups are best used for complete restore, there are better solutions for short-time backups or single restore actions, like clouds, distributed HD cabinet stacks or simply backing up stuff to external HDs or even USB sticks. Most admins/IT depts. of larger companies with lotsa data to backup combine short-time and long-time strategies to prevent data loss.
Typical backup strategies cover three major aspects: Desaster recovery (which includes the OS), full and single data restore. Desaster recovery is used to restore a complete OS/system after a major hardware failure and should be implemented so that it's possible to also recover the OS data to completely new hardware. Full and single data restore refers to normal, non-OS data like word documents, pictures and stuff like that. If you're a company admin, it may also be required to backup databases or virtual servers which requires different strategies (or proper software), you can't just create copies of database files and simply restore them one by one, this may work with early version of MySQL but do it with Oracle and it will break. A good backup software comes with drivers for these special cases that enable it to suspend a running db and make a time-based snapshot of the data which can be restored easily. Same goes for virtual servers.
Of course a tape-based system may not be the #1 choice for private data backup, here, creating complete images of your system(s) (for ex. with Acronis) and backing up data that changes a lot to a cloud, external HDs or DVDs is more convenient and cheaper.