tezos is attempting to solve this by incorporating on-chain governance - its dPoS and has a code deployment mechanism with a long voting process (multimonth). They have done 2? upgrades now and quorum seems to be ok so hopefully they can keep up voting %
i still think the nano (formerly raiblocks) approach is cool - it scales by running parallel blockchains - each wallet is its own chain. tx's between chains are voted on weighted by % stake - dpos without lockups or slashing. this way its not a competition for space in a single ledger, its competition for voting bandwidth on the worst marginal node. a better tradeoff imho. downsides: the ledger also grows larger quicker than btc (because theres no 7tps limit so you can spam it)
no voting rewards or inflation - theres no on chain incentives for voting at all, but exchanges/pos need to run full nodes to validate ledger anyway and voting is trivial bandwidth. its elegant and the security model works but its hard to tell people about without coming across as a fanatic.
Because nano has free transactions, a big concern was indeed spamming the network because transanctions are free (as in you pay no nano). But since each wallet has to calculate their own blockchain, the prosessing power is purely on the client side and so not free in that sense, which limits the spamming to the processing power you have.
Recent spamming [1][2] has seen nano ledger size balloon by nearly 50%, negatively affecting full node Initial Block Download times as well as archive node disk space requirements.
The PoW requirements go up with network congestion, but at this rate of 5-8 tps are quite minimal.
i still think the nano (formerly raiblocks) approach is cool - it scales by running parallel blockchains - each wallet is its own chain. tx's between chains are voted on weighted by % stake - dpos without lockups or slashing. this way its not a competition for space in a single ledger, its competition for voting bandwidth on the worst marginal node. a better tradeoff imho. downsides: the ledger also grows larger quicker than btc (because theres no 7tps limit so you can spam it)
no voting rewards or inflation - theres no on chain incentives for voting at all, but exchanges/pos need to run full nodes to validate ledger anyway and voting is trivial bandwidth. its elegant and the security model works but its hard to tell people about without coming across as a fanatic.