One of the things with the Titanic was that it's crew was not experienced enough with launching lifeboats. Whilst most had served on other vessels, the Titanic was using newer Welin davits for the lifeboats (they differed from earlier designs still in use on other vessels). Even if she had had enough lifeboats it is doubtful whether the crew could have launched all the boats in time (they were still trying to launch the last two boats, Collapsible's A and B, when she started to make the final plunge). More would have been saved if there were more boats no doubt but even so, you need time and a crew that has clear instructions on what it is doing.
The Lusitania is a prime example of what happens when there is little time to evacuate a ship. She sank in roughly eighteen minutes and got only a handful of her boats away successfully, not least because the ones on the starboard side swung away from the ship whilst the ones on the port side smashed into her hull.