they'll never print a card pack of existing cards, sorry. It would be unprofitable, plain and simple.
I'm trying to think how it would be unprofitable when it is desireable to have lots of upgrade cards but one might not need/want the ship needed to get that card. Are you trying to say they will make more money by linking the cards to ships, and thus forcing people to buy multiples of ships they otherwise would not? That could be true, but I also think there are probably people out there that see no need in having multiple YT-1300s or Firesprays but would buy a pack of cards that included the upgrades/modifications that come with them.
They already make a separate dice pack. I see no reason why we wouldn't, down the line (after another wave or two), see packs of upgrades and modifications. It really depends on what direction they go though. As people are quick to point out, we are quickly running out of ships that A) appeared in the original trilogy, and B) fit the scale of the game.
in so many words, you're saying you want to buy the bare minimum of product necessary to build your dream squadron. If you want multiple copies of Stealth device or Engine Upgrade, then I disagree: you do see a need in having multiple YT-1300s or Firesprays.
It's not in a company's profit interest to enable people to buy the bare minimum of their product. They put out expansions that have ships and cards; if you want a certain card, it's in certain packs. You know what to buy. It's a strange definition of "forcing people" to put out a product for people to buy and hope that they actually buy the product.
I don't consider it to be "forcing me" to buy all the Baratheon and Lannister and Martell cards I'll *never* use for the Game of Thrones LCG. I'm not demanding that they split up their chapter packs into mini packs containing just the factions I care to play.
While the cards in question (Stealth Device, Engine Upgrade) do only come with the Slave I and YT-1300 right now, other upgrades are found in multiple places. It is clear they are not "married" to a certain ship. Thus, it should be simple to understand that one could see no need to have multiple copies of a ship they only ever plan to play 1 of at a time, but then have a desire to own more of the upgrade/modifications that come with said ship. Need vs desire. Personally, no matter how bad I want 4 Stealth Devices, or 4 Engine Upgrades, I have no use for 2 YT-1300's or 2 Slave I's. The cost of them is too high just for the modification/upgrade cards, in my opinion. I will not be spending additional money on those expansions. If those cards are re-released in another ship expansion, I'll likely buy it as it is (at this point) probably a new ship (in other words I'd more likely be buying it for the ship, not the upgrades). Now if they were released in a multipack of just upgrade/modification cards, then I would definitely be spending more money, money that I am not otherwise spending on FFG products currently. The question is, overall for the whole game and all its players, is the amount gained from upgrade/modification packs more or less than the money lost because some people are willing to buy those extra ships just for the cards? I don't know the answer to this.
As for your example, if the faction cards you did want were not in those chapter packs, would you buy them? Based on you not wanting cards for factions you don't play, I would assume no. So really, to get the cards you want you only have 1 option. You have to buy the whole pack. So yes, you are forced to pay for something you are not going to use, in order to get something you will use. Is anyone making you buy the game at all, no. Let's not get into the semantics of forced. I think it was pretty obvious I was indicating that in one scenario people end up with something they don't want because they have no other option to get the thing they do want, and in the other scenario people can pick and choose.
Anyhow, you specifically said unprofitable. All I did was point out, in so many words, that less profit is different than unprofitable. My guess is that letting players buy the bare minimum of product would still turn a profit, it just might be less profit than the current set up.