First, most chins don't actually like to be held, like I would say at least 90% of them hate being held. With time most can learn to tolerate it though, like to the point of allowing you to take them to the play area or put them in a carrier when needed (like to go to the vet). It can take years to get to that point though, and if they were ignored or even mistreated (kids often don't know how to properly handle chins), it can take up to as long as they were treated that way for them to come around and trust again. So if they lived years not getting properly handled and attention, it very likely could take years for them to get over it and start to really trust you.
They aren't animals that blindly trust, you have to earn it and prove you are trustworthy, and if you do anything to prove you aren't trustworthy, like grab them or have to chase them to get them back in the cage, it can cause you to go a few steps back in the process. You say you talk to them, but do you just sit by the cage and be with them? You can sit by the cage with the door open and allow them to come to you and sniff and explore you. Do they ever come to the side of the cage to greet you when you come in the room? You can try offering a small chew toy, treat, chew stick, or hand them strands of hay ( either a type they don't normally get or some chins especially like specific parts like the seed heads for example) or even just hand them pellets. If you come and go from the room often you can split the food up too, make sure they always have hay but each time you come in the room you give them a little bit of their daily pellets so they start associating you coming in the room with good things.
Another thing, although most chins love running around outside the cage, not all chins seem to, if they have a large cage with lots of things to entertain them, play time might not be as appealing and they may feel safer in the cage or at least near the cage. Would it be possible to set up a play pen around the cage so they can just hop in and out of the cage as they want during play time? or even move the cage into the play room, even just for playtime, so they can go back in their cage if they want?
If not, they aren't like dogs that need daily exercise, so if their cage is large enough they are likely getting enough exercise in the cage. If they don't already have one you can also get them a chin safe wheel (soild metal running surface and 15-16" diameter) to use. Daily interaction is much more important, so long as you are spending at the very least an hour or two everyday with them they are likely fine in the cage most days.
