All of these organisations you mention are in it to make a $..
Therefore they continue to develop new features and generally try to stay ahead of the competition.
Your question is really about backup..VMware don't really want to be a backup provider.. They dropped VCB which was a fiddly backup method but one that worked quite well once setup correctly. VMware's replacement backup product for VCB was targeted at small sites. VMware data protection..which was appliance based and as now would only write to effectively a disk pool..
Stepping up to the next level of backup in the VMware space is where you install your choice of product and use to the VMware Storage API's to effectively grab the virtual machines..or the CBT (block change) data from a guest.
Personally I would not use VMware's data protection appliance. There are better solutions available many of which are free. (with some limitations)
These can write to disk or tape. To these products Disk or tape it doesn't matter. It's just a storage medium..
Why wouldn't VMware be too bothered about supporting tape storage mediums.
* They are not a backup provider.
* Tape Technologies are a technology of the past. Hard drive, both spinning and SSD are the future.
* VMware are owned by EMC. EMC own DataDomain. (NetApp have a similar offering to DataDomain).
What to do????
Look at the Veeam Backup and Replication.. Even the free version can do scheduled backups with a bit of scripting. (although it can not access the CBT function)
Buy the full version of Veeam it can access all features..
There are many backup products on the market all with similar features, but the Veeam products are quite good..
If your in a larger shop you might well be a TSM shop.. Again IBM have TSM 4 VE which is an excellent product although quite complex to setup.
Where I suspect your at !!
If your just starting out and you want to have a fiddle stick with Veeam Backup and Replication. Go the free version and learn about the scripting side. Buy an icy cage and some 6TB NAS hard drives.. This will be a short term backup solution as you grow into virtualisation.