I have probably heard less convincing apologies in my years as a litigator, but I can't recall one offhand.  From the story, few of the victims were convinced either.

The taxpayers will now spend hundreds of thousands or millions pursuing appeals and habeas remedies that knowledgeable people regard as ranging from dubious to absurd.  None will be absurd enough, however, to contest his factual guilt.  If we need to save money in the criminal justice system, this would be a good place to start.

There is not a whole lot left to say about this awful case.  The best capital defense lawyer in the country could not convince a single juror sitting in Boston, of all places, to vote for LWOP.

A sensible system would execute Mr. Tsarnaev promptly and move on to the next abolitionist poster boy, Dylann Roof.  But a sensible system would not tolerate the delay and expense already built in.