NCT TRACON Controller reported SFO departed one aircraft on the SEGUL Departure and another aircraft on the SSTIK Departure; which made maintaining adequate separation unfeasible for Departure Control.

Narrative

SFO launched an aircraft on the SEGUL Departure with a SSTIK Departure at minimum separation behind; an issue that has been a recurring safety concern for us. Today; an aircraft on the SEGUL Departure was issued a vector off the procedure to mitigate potential conflicts after the Tower launched another aircraft with exactly 3 NM of separation. However; due to the differing lateral paths of the two departures; maintaining adequate separation became unfeasible for Departure Control.At their closest point; the two aircraft were 2 NM apart and 500 feet vertically; demonstrating the risk posed by this procedure. To manage the situation; we assigned a heading to the SSTIK Departure aircraft (a business jet) and issued an altitude restriction to ensure separation.Recommendation: I don't know what more we can say. This has been an ongoing issue for far too long; and despite everything I've personally done to get this departure fixed; I keep running into bureaucracy and red tape.I've had meetings with SFO Tower and ZOA; pushed for changes internally at NCT; and yet nothing changes. This departure is dangerous; and yet no one seems to care. We are raising a legitimate safety concern; taking all the necessary steps to mitigate the risk; filing reports; and still nothing. We have submitted multiple routes that could be issued instead of the SEGUL and are constantly met with pushback - nobody seems to care. What more can we do?Reporting exists to address systemic issues; and we've been fighting to fix this specific problem for over six months. Something has to give. This departure injects unnecessary risk into the system; and I have to ask what exactly has to happen before someone finally takes this seriously?People shouldn't have to die to spark a safety culture. We have been sounding the alarm on this departure for months. It's past time for action.