With capped coins, transaction fees must be large enough to prevent major miners from defecting. So, they need to support large number of transactions to have a stable value store.
transactions are limited to ~10/s
[...]
At high volumes, this will approach the petabyte scale
This is a big reason why many people want to keep the transaction size small. Currently, hard drive size is expanding faster than the block chain.Segwit makes it a lot harder, and as segwit adoption happens it will be a lot cheaper to transact, even when the spammers are spamming.
Here is a quote from the bitcoin.pdf white paper: The cost of mediation increases transaction costs, limiting the minimum practical transaction size and cutting off the possibility for small casual transactions...
If your vision of the future of Bitcoin is simply "a store of value" then I think you are missing out. There is a lot more value to disrupt by making transactions more efficient, and I hope the Bitcoin of the future will evolve to tackle this problem.
However, these barriers do not mean Bitcoin is doomed to fail. Logically, there are two paths to success: (1) Bitcoin is rearchitected to handle high volumes or (2) Bitcoin succeeds in low-volume applications.