They absolutely can. We just think that unless there is an economic difference from bitcoin and other existing p2p issued coins, there's absolutely no justification for doing so.
I am not sure how b) would be possible without a)
You realize that bitcoin has the same problem, once the subsidy drops to a negligible amount?
Transaction fees are one solution, or you can have the coins demurrage in the side chain allowing for a perpetual reward. (Demurrage with pegged currencies is possible, as the pegging mechanism provides friction). There are other mechanisms being considered as well.
While this seems like a nice way to experiment. I am not sure what are the incentives for the AltCoin developers (zero profit).
Approximately the same incentives as Counterparty, which also forgoes the scummy currency issuance model.
The asset issuance and smart property contracts layer is free infrastructure that is difficult if not impossible to monetize directly, yes. But there are an infinitum of profitable services that can be built on such a layer.
Defending 'type-b Bitcoin' as economically viable (with unlimited one way issuance) shows a complete misunderstanding of very basic economics - in order for proper functionality as a store of value, or financial instrument (it's not the same as buying your bitcoins in the morning and spending them for some lsd on silkroad in the evening - the medium of exchange type use) - there has to be a relative stability in price (or minimally the instability has to be relatively predictable). In this case it is completely unpredictable - because you always have to sell to someone to get regular Bitcoins, but they never have to buy to get type-b bitcoins: no one is going to use a decentralized system that is far higher risk than a centralized one.
Furthermore here for example is the last block: 295094
Reward: 25 btc
Fees collected: 0.05852852 BTC
25:0.05852852 That's .00234 - So we can expect .234% of the total hashing power working on the type-b bitcoin chain (if it reaches the same transaction volume - unlikely, and actually less considering the ridiculous one way redeem-ability). And this is going to be a secure network?