The reason so many New Year Resolutions get dropped, is because people start doing something out of the ordinary (for them) in order to institute a change, but never make that change a habit. It’s the reason dieting does not work – you shouldn’t go on a diet, you should change your diet. The former implies a one-off activity that will somehow leave you better off – and it may for a short period of time. The later states that you will change your habits, so that now on you will do something differently, from this point forward.
When people embark on a Great Rewrite, they are undertaking the equivalent of a crash diet. Sure, you loose a few pounds, but when the old habits come back, and the diet has finished, all those pounds come back. Rather than kid yourself that by starting afresh you’ll learn from your old mistakes, start making changes in what you do now. In other words work to change the diet you have, the system you have – that will lead to habit change which will stick. It’ll also force you to deal with the problems you caused in the first place.
Working to change the system you have now has other benefits – other than being more likely to institute a change that sticks. It makes it easier for the whole team to be involved with the change, rather than leaving some people supporting the old system. It allows you to trade-off delivering new features and bug-fixes against architectural changes. But perhaps most importantly it helps create a team which understands that fixing a situation – improving it for the better – is possible and achievable.