I'd always assumed that the return of Caldari Prime wasn't such a huge concern for the State, honestly. Taking the planet back during the war of secession wasn't the primary goal, independence was. They knew they were risking the planet when they seceded and decided that risk was worth it. They were quick to evacuate the planet and the heart of their population and most of their resources were off-world. At the end of the war, the CEP made little effort to claim Caldari Prime, because it wasn't particularly useful to them.
To be fair the State had been on the back foot for just about the whole war and their military effort was focused on surviving as a sovreign entity. Vastly outnumbered and outgunned by their leviathan opponent their military strategy seems to have been one of total mobilisation and attritive attacks on the will of the Gallente to continue to wage a war that had become incomprehensible to most of their citizens.
Under the circumstances I don't think it was ever possible for the State to win back a foothold in the Luminaire system.
That said, just because realpolitik ruled it out, doesn't mean it wasn't a heavy blow. If you look at the central tenets of Wayism, you can see they are based on ancestor worship and a sort of animism focused on nature worship. Certain mountain ranges are sacred. Many of the chief deities are Winds specific to the Homeworld. It's hard to believe that a culture so organised could face the loss of it's homeworld without an aching sense of loss and shame.
Then you have the toast "Haak-kin k’len" which translates as We (the we that is all of us and also you) shall return. Although it's not stated explicitly that this refers to Caldari Prime, it's fairly obvious that it does indeed do so and that it acts as unifying impulse in the Caldari State.
Don't get me wrong, I'm sure many Caldari were unhappy that their homeworld was in foreign hands, but I think they were, by and large, resigned to it. There certainly isn't much PF portraying the wound as an open one. . . until Heth. I think it's a mistake to portray Heth's focus on retaking the planet as a continuation of Caldari foreign policy, when I think it's largely his baby, though one that would win him popular support after he'd gone and done it.
You, perhaps, have to compare it to the Argentine desire to claim the Falkland Islands. I agree that few Caldari ever expected it to happen in the near to midterm, but I suspect that articulating the doubt that it would EVER happen is close to treasonous. It is probably seen as a point of shame that the homeworld was lost and had not been recovered and I'm pretty sure that now that a Caldari Fleet is in orbit around it, the State would not soon forgive the men and women who bartered it away like goods in a peace settlement or who allowed it to be lost once more.