We don't know if 1% would be necessary, or if it would be sufficient. I think that an in-depth analysis would make a great research paper.
It is not clear if it would even be viable. How would you feel about your bank charging you a 1% security fee to hold your money?
To maintain a fixed money supply, the 1% subsidy could be accompanied by a 1% demurrage.
no matter how it's implemented, paying for mining security is experimental. we don't know if fees alone will be viable either. that's one of the reasons i'm a small blocker. i want to err on the conservative side re the assumptions we make about security absent a significant mining subsidy. if that damages adoption potential, so be it. adoption shouldn't come at the cost of viability.
there are basically 3 ways we can pay for mining security: 1. fees, 2. inflation, 3. demurrage......or some combination. none of these are attractive to users. nobody wants to pay large amounts just to send money. nobody wants to have their money devalued by inflation. nobody wants to be charged money just for holding it.
still, we need to pay for mining security somehow. and since economics can't be studied empirically/scientifically, we're all just guessing at what the best solution is. we're also tempering that against our own selfish drive towards a tragedy of the commons, where we sacrifice long term viability because we don't wanna pay any of the costs. that's partly what is behind the motivation for big or unlimited block sizes---the other motivation being that it's a marketing point for adoption. you know, "cheap/instant tx".