It looks as if the problem was due to the boat getting stuck on something under the port bow (which is what the account of what happened said), and this then wedged it in the narrow lock tail -- which won't have helped, but it's not really a "normal boat now getting stuck" simply *because* the lock is too narrow, is it? Otherwise there would be multiple reports of this happening with "normal" boats (not wider historic ones...) at this lock.
Of course in an ideal world it ought to be fixed, but if it's not normally a problem for most boats I'm sure CART have got more pressing things to do with the money they haven't got than spend a fortune rebuilding a lock (and closing the canal for months). If it gets narrow enough to really be a problem they'll have to do this, like they've done at other locks (e.g. Hurlestone), but I can't see it happening for a one-off accident like this.
I'm sure this will (justifiably!) p*ss off historic boat owners whose boats get caught in tighter locks (like this) first, but CART have to prioritise things which cause problems for most boats not a few -- and yes the same could be said for dredging, where deep historic boats drag on the bottom first. But as everyone is well aware there isn't enough money to fix everything properly, so it's all down to priorities, and problems suffered mainly by a few historic boats are going to be well down the list... 😞