NASA's SLS rocket. Questions about it

On Friday, February 15, 2019 at 9:35:19 AM UTC-5, Chris L Peterson wrote:
On Fri, 15 Feb 2019 06:11:21 -0800 (PST), RichA
wrote:

On Friday, 15 February 2019 06:13:39 UTC-5, wrote:
On Friday, February 15, 2019 at 1:20:03 AM UTC-5, RichA wrote:
The SLS is the next giant rocket that will be used for long range manned spaceflight, or the moon as a target. But it's way over budget (how much is really left for it after the ISS sucks up so much?). Some of the technology being used to built it is different. Like friction welding to put the tanks (outboard, like the Shuttle) together in sections.

https://www.nasa.gov/exploration/systems/sls/index.html

So what were the questions?

I guess the main one is, why didn't they just rebuild the Saturn V or create a minor variant? The stages of that rocket were disposable as are the rocket boosters (a la the Space Shuttle) on this new one, so why re-invent the wheel and risk unforeseen problems developing as well as dragging out the initial launch time to the mid-2020's?

Too expensive. Too unsafe. Too full of obsolete materials and
technology.

(Of course, it's not clear why we need a heavy lift vehicle at all.)

Not clear to you, obviously.