First off, how much res does it cost to get jetpacks? Let's count
10 for armory
20 more for advanced armory (which takes 60 seconds to research)
30 for proto lab
25 for jetpacks (which take 90 seconds to research)
So thats 55 tres for jetpacks. And that's for rushing them too, not that it's a good strategy. But this doesn't highlight the real problem with jetpacks.
Jetpacks are slow, inefficient, and there's often nowhere to actually USE the jetpack to your advantage. Let's take summit for example.
Nearly every hallway has NOTHING to get on top of; once your jetpack fuel runs out, and it's going to run out REAL quick because of how inefficient it is, you're going to fall right back into that Onos that's rampaging everywhere. This isn't to say that it's just a map problem, but it's also a mechanic problem. Mappers wouldn't have to cater so much to thinking about how jetpacks are going to affect their maps if the jetpack wasn't so atrociously inefficient. I haven't played NS1, but I've often heard people vouch about how good that jetpack was. What ever happened to that idea? I know exosuit is also going to be researched from proto lab, but come on. It only costs aliens 40 res to get carapace and 25 for augment, that's only 10 less than it costs for the overall cost of getting jetpacks. That isn't to say that it isn't a problem with the lack of alien res sinks but come on, 55 res for something that's only useful HALF the time? And often times the RT areas don't even have places you can jetpack onto like reactor core.
Why do jetpacks have to be so inefficient for something that is suppose to help us counter the massive alien behemoth that is the Onos?