Book stated that his ship could achieve quantum slipstream but he lacked the benamite to do as it was apparently as hard to come by in the 32nd century as it was in the 24th. Benamite could be synthesised but it decayed quickly and was inherently unstable. So it seems to be a combination of a lack of naturally occurring benamite and the synthesised crystals not being adequate. Obviously Arturis's people were able to either find natural sources or effectively replicate reliable crystals. But given that they were able to evade the Borg for centuries and the Borg themselves had been around since the 1400's, Arturis's people were 1500 - 2000 years ahead of the Federation technologically, possibly more.
Actually no.
Arturis' ship (the Dauntless) did not use benamite crystals for achieving quantum slipstream.
Voyager was able to adapt that first iteration of the drive to its own warp core with a few modifications (and Tom Paris mentioned that the energy from the quantum drive has been routed through the deflector dish - which is what appeared to have been creating the Slipstream) but was subjected to quantum stresses which didn't allow Voyager's hull to maintain Slipstream for longer than 1 hour.
And this version of the drive allowed a maximum speed of 300 lys per hour (in the late 24th century).
For sustainable cruise velocity, the speed would have to drop to lower levels (about 714.28 Ly's per day) in order to get the crew back to federation space (60 000 ly's away) in 3 months as the fake message implied.
It wasn't until 4 months after those events that the crew developed their own version 2 of quantum slipstream technology which used a combination of Borg technology, quantum matrix and benamite crystals (which was also much faster than Arturis fake Dauntless QS drive... topping out at about 10 000 lys per minute).
So no, Arturis species was not 1500 to 2000 years ahead of the Federation. Not by a long shot. Maybe 50-100 (possibly 200) years at most (and mainly in areas of propulsion and particle synthesis).
Why? Arturis' is just 1 species. The federation is comprised of over 150 member species working together. Exponential developments and return would be radically in Federation favor (also, the fact voyager was able to knock off fake Dauntless shields with a couple of photon torpedoes means the Federation was far ahead of Arturis species when it came to tactical technology).
This is also why a lone Starfleet ship can reverse-engineer alien technology pretty fast and adapt it to their own.
Any species can evade the Borg if they're aware of them. The Federation was not technically aware of the Borg before the Q flung enterprise d in front of that first cube.
Even so, Starfleet should have been able to make even version 1 of quantum slipstream functional since that would only need a redesign of a ship's hull or enhanced structural integrity fields so they can cope with quantum stresses (and doesn't need benamite crystals to run). So even if Starfleet was sitting on their laurels for the next 800 years (which is utterly ridiculous), they'd still have a basic Quantum slipstream technology which would be able to traverse 60 000 lys in 3 months (or max out to 300 lys per hour for limited periods of sustainability in cases of emergency - answering distress calls, relief efforts, quick defense... etc.)
Also, whatever happened to the notion of Starfleet being able to recrystalize dilithium since late 23rd century?
Clearly the technology existed in the 24th century.
But more to the point, dilithium and M/AM would have faded into obscurity by late 25th century.
Look at fossil fuels today... the only reason they 'endured' this long was because of ridiculous subsidies they receive from across the globe (and renewables are rapidly replacing them just over 100 years later)... its not that electric vehicles or other types were impossible or not capable of replacing it decades ago... of course they were... electric cars even with limited range were more than practical for urban areas.
Power generation was never constrained to fossil fuels... we also had Geothermal since 1911.. and Thorium since mid 20th century.
It is HIGHLY unlikely that the Federation would have continued using dilithium and M/AM after the late 24th century (heck, even the 24th century is pushing it as is, but whatever) even if you wanted to use real world for a basis.
Why?
Well, as I mentioned above, technology and science evolve at an exponential pace and you get those returns at an exponential level.
The Federation is comprised of dozens of species in the 23rd century and over 150 species in the 24th century.
That's 150 different scientific perspectives with millions of scientists per species, with highly advanced automation and computer technology at their disposal.
Computers in the 24th century could accurately predict events in holgoraphic simulations with just a few words... this alone would easily propel science and technology ridiculously forward based on just what the Federation had in its database BEFORE Voyager went into the DQ.
