What's the rush to travel forward in time?

Question

In the 1984 events of Terminator: Genisys when Kyle and Sarah, having destroyed the only known enemy robot in their timeline, approach their one-shot Time Displacement Engine (TDE), they get into an argument about whether they should travel to 1997 or 2017.

• At no point do they question whether they should jump forward in time at all.
• In either scenario, their goal is to travel to a point in time that is mere days ahead of Judgement Day (i.e., Skynet going online).

I suppose it would be tedious to watch them prepare over years to thwart Skynet/Genisys, the way Sarah did in the previous timeline (T1-T3). And given the poor dialog I can see why the producers would have been happy to move things along. But is there any internally consistent reason why there would be any urgency to jump forward in time to stop SkyNet?

Presumably any future enemies with access to a TDE would have already sent back as many soldiers to kill them as possible. I.e., time doesn't run concurrently. It's not like the future enemy just learned something from its T-1000 having failed and been destroyed: All it knows is that it sent one (or more) T-1000s back but that Sarah Connor and the resistance still exist in its past.

So travelling forward at the normal rate could only be a good thing:

1. They could stockpile weapons, tactics, and allies (as did Sarah Connor in T2)
2. They could gather intelligence
3. Most importantly: They could avoid overshooting the critical point in time at which Skynet could be stopped.

Also, by not using the TDE to travel forward they could reserve a potential "do-over" to jump back in time should they fail.

Answer 1

So travelling forward at the normal rate could only be a good thing

No, it would be the opposite. Sarah and Pops only waited because they needed a Future Tech cpu to power their homemade Time Displacement Engine.

Waiting longer could risk being injured, or loosing strength, being caught stockpiling weapons, having the TDE being discovered (it's tapping power from the entire city), having Pops get destroyed and his tech discovered.

Any errant car or bullet or anything could kill Sarah, causing irreparable harm to the timeline and the rebellion if Skynet wasn't stopped.

having destroyed the only known enemy robot in their timeline

Not true. They had destroyed The original Terminator, but also a T-1000. In the original time-line, the T-1000 was sent to 1990s, not 1980s. Sarah and Kyle would be in continuous risk by taking the long way to kill Skynet before its born. Remember, The Infected-John was active in the 2010s! That means they would have risked multiple years of death while trying to stop Skynet's activation.

Based on Sarah's reaction, the plan was always for Pops to accompany her in the TDE. The plan changed the minute that Pops' skin get compromised, hence he needed to take the long way around.

Also, waiting 30 years, they would no longer be in their prime. 50 year old Kyle and Sarah may not have been strong enough to take on any resistance. Even Pops was showing signs of age related problems. Old.- But not Obsolete.