Besides the lovely explanation to why given by Darzil.
Deckers and Street Samurai require funds to do there jobs, which are both gear based. Street level encourages MagicRun, because it is the only way to make characters that can survive. You dont have funds for it really otherwise. Prime Runners have the funds at most priority levels to be able to buy a deck.
If security is an air tight lean mean shadowrun eating machine, then yes, you need top of the line gear. Against, Timmy, the pimple faced part time rent-a-cop, not so much. And there are lots of layers in between. What I am saying is, if you calibrate the difficulty level for your team right, the rules and equipment should hold up well. At this point, I do not see enough evidence that the rules can't hold up well as is as long things are thought out properly.
Shadowrun 5 appears to be more about depth of character including flaws in both the runners, their gear and the forces they are against. That's a huge dynamic outside of simple dice rolling and statistics. Then again, in my last group, our most famous street sam was a 2nd edition unaugmented ork who played it smart and was deathly afraid of bugs having jumped on a chair and screamed like a 5 year old girl when a spider ran across the room (before any advantages and disadvantages) causing one huge gun fight, chase scene and a lot of patients for docwagon (namely the other PCs).
The one area I do agree with (barring evidence otherwise) is that more options for decks to be modified and upgraded along the way would be nice. As many have pointed out, a deck (and the right vehicle for riggers) is a major investment and players will be using it for a long long time.