What happened the the 49ers defensive pass rush?

Ive noticed the 49ers defence seemed to loose thier pass rush.I think other teams are starting to exploit the defensive secondary because the 49ers defence seemed to loose their passrush.I think we might want to start blitzing more on defence

All these magic defensive plays that Fangio was going to install seem not to have materialized, the 49ers are making almost every OL they play look overly imposing. I don't think Aldon can pull off the full-time role, he has shown he can tackle, play the run and cover decently but he doesn't have the fire and explosion on his first step to get past guys instantly. Justin Smith is still damn good but he played at pretty much a career high last year. This defense could have strongly benefited by adding an OLB in the 1st or 2nd round, or even a 3-4 DE like Derek Wolfe, they really overestimated their strength.