Roughly 1500 died on the Titanic; according to Wikipedia, it would have cost about $16,000 to equip her with additional lifeboats sufficient to save them all. Call it $10 per life saved. The price level today is roughly 22 times what it was in 1912, so in today’s terms that’s $220 per life.
Now, if I were boarding a ship for a luxury cruise, and was offered the chance to pay an additional $220 for a guaranteed seat on a lifeboat in the event of a sinking, I’m quite sure I’d take a pass — and I’m quite sure so would virtually all of my fellow passengers. So if the Titanic had been designed to cross the ocean once and then spend the rest of its days in a museum, it would have been insane to equip her with extra lifeboats. But of course if the Titanic had been designed to cross the ocean once and then spend the rest of its days in a museum, it would have been insane to build her in the first place. So that’s not the right calculation.
The right calculation accounts for the fact that a single lifeboat provides security to passengers on multiple voyages. How many voyages? Well, the Titanic was intended to make the round trip between Europe and America every three weeks; that’s two voyages per three-week period. I’m not sure how long the sailing season was, but we know it was underway by mid-April (and perhaps earlier; it’s often mentioned that if the Titanic had been ready earlier she would have sailed earlier) so (assuming sailing conditions are roughly symmetric around the solstice) it must have lasted till at least mid-August. That’s time for five round trips at a minimum, and I’m guessing this is a quite conservative assumption.
If a lifeboat lasts a year, then, it does its job at least ten times. If it lasts five years (which is, I suspect, another quite conservative assumption), it does its job fifty times. Now we’re in the vicinity of $4 per passenger (and of course much less if my assumptions are indeed quite conservative).
Okay, now if I were boarding a ship for a luxury cruise, and was offered the chance to pay an additional $4 for a guaranteed seat on a lifeboat in the event of a sinking, I might still take a pass, though it’s not quite as easy a call at $4 as it is at $220. But a good rough empirical rule of thumb, for low-probability disasters like this, is that most people value their lives at something a bit south of $10 million. So for most people to want the lifeboat, you’d have to believe that the chance of sinking was better than one in two -and-a-half million. Those are roughly the same odds you face when you board an airplane today, and I’m inclined to doubt that a 1912 ocean cruise was substantially safer than a 2012 airline flight.
So yeah, it seems like they should have had more lifeboats. But all the people to whom that was instantly obvious must sure be a lot quicker at mental arithmetic than I am.