If Gavin is worried about not being able to fork after the next potential burst why not apply Justus idea [1], too much coding with not enough time?
[1]https://bitcoinism.liberty.me/2015/02/09/economic-fallacies-and-the-block-size-limit-part-2-price-discovery/
Because who pays for that coding? And who can be sure that the proposal, even if completed and tested, will be adopted?
Andresen's position seems to be: (i) he takes responsibility for coding and testing a solution that as far as he can see takes care of the issue well into the future (ii) he does this with sufficient time for others to analyze it, so that, whatever else happens (iii) there is at least one safe fall-back option.
Can he guarantee his proposal is optimal? Of course not. It is just quite reassuring for it to be out.