Thanks for this thread OP, some interesting views were discussed, and it's a nice change to see some organised thoughts instead of the usual "TOOMUCHGRIND,I'MOUT" threads.
I've been in the same situation as yourself more than once. For a good 8 months, I only logged in maybe once a week, for the sole purpose of opening the galaxy map, and check my faction's status. If nothing was happening, I'd close the game and play something else.
When 3.0 dropped, I wen't back in to investigate the changes, try a few things. I had a tiny objective, to build a stealth Sidewinder, no shields, a railgun and a modded beam laser to keep the ship cool.
That was a silly objective, but it only took me a few minutes to outfit by salvaging some of my modules, and engineering the rest to tier 1 or 2.
Then I could put that ship in arms way, and I had a good laugh trying to take on a Terrorist Leader for a wing assassination mission.
I was sort of hooked again, but I needed materials, so I outfitted a collector limpet to most of my ships, and I started to do some of the new missions, picking every material I came across with my limpets.
After a few sessions of random activities supporting my faction, and lot of research on third party tools, I figured I had enough mats to finish upgrading my Corvette, with the sole purpose of being able to solo Elite wing assassinations (not too much of a challenge, but good enough for me).
And that was fun!
I mean, the upgrade process itself was a chore. With the help of a good old pen and paper, I had planned my upgrade process, taking into account material traders and engineer bases.
Then I had to fly a Corvette with 17ly of jump range all over the bubble for the better part of an evening.
But after that, I could massacre those terrorists, and that was my reward.
So yeah, in the end what motivated me to start the game again was to have a quick objective, that I could enjoy right away, and it motivated me to do bigger projects.
I'll keep playing for now, until I hit my next motivation-killer