My Samsung smart tv wont download any apps or startup any.?

You have an old TV, running on outdated software and hardware, and Samsung can’t control or force other companies to continue support on technology that’s outdated.

Imagine grabbing an old PC, and trying to play today’s games or VR titles on it. It won’t work, and you can’t look at Dell and say what’s the point of having a computer if I can’t play VR games on it. The software and hardware is limited, and can’t handle it.

I’ve always recommend getting an external streaming device, such as an Apple TV or Nvidia Shield. Not only would you get a far superior picture quality and better streaming experience, but it will put less strain on the TV. Plus, it’s easier for streaming companies to use that platform because it’s a device that isn’t changing its hardware/software every year like TVs. Apple hasn’t updated their 4K streaming device since 2017 and their 1080p since 2015 (I think) which makes it easier for Netflix, Hulu, and Amazon to update and work on their platform because they don’t have 20 models to work with for 2021, another 20 from 2020, and 2019, 2018, 2017.... see what I mean. Eventually there will come a point where they have to say “We are ending support on devices 8 years.”

Getting a streaming device will be far better for you. You’ll get access to more apps that isn’t on Samsung even now.

The problem is almost definitely that your TV hardware is now too old to run an operating system which is compatible with even the most basic versions of the apps you want. 

That TV is now eight years old, and the hardware design internally is probably about ten years old. 

I don’t know any smart TVs that old which still have support for their smart functions.

You don’t need to change the TV though. Just connect a suitable modern games console, or plug in an Amazon Firestick, Roku or similar device to an HDMI socket. 

They will run the latest app variants and will effectively replace the smart hardware on your TV.

EDIT: The point is that yours was once smart. Now it’s old enough to have gone senile. Old electronics become obsolete. Why do you expect your TV to be a unique exception? At least the TV part of it is clearly still usable and at low cost you can make it smart again.