Most (if not all) shipgirls become available later through drops and/or construction; and it's also usually the case that ships that were in an event, either as drops or rewards, become drops in the subsequent event also.
That's not to say that they're easy to get, draining either SAN or resources in abundance for the slim chance of appearing, but they're there.
Yweeeeef?Erm...I'll get her...for sure......mrgzzzzAh...Ah...!Excuse... me...Ah...Admiral... I-13... has been posted.But...Just let me... rest for a... bit...Sorry, yeah... I haven't managed to find your older sister yet...I'm Hitomi...I'm not my sister...No...Well...Hmm...? Oh.... it's you, Iyo.I-If you're going to take a break...Eh...?wibble
wobblecrrrrkI know, okay?I'll get her back here, no matter what...It's better to go and lie down properly...!I've got plenty of reserve resources, but the sortie fleet (and my) fatigue's limit is fast approaching... When considering the remaining time for the operation, I really can't take this too lightly.toktokflpPutting this all together here is having the opposite effect...
Maybe I really should just take a short respite to collect myself...?