zip up the asthetic / unused old stuff per directory -- can even leave the archive in there if you wanted to.. i'd suggest a safe "off-site" location.
the images and news and just about everyhting can be compresses ~99%. maybe just he text stuff reaches 99%, but it's more than it looks like. you also save on 'blocks'... a 1kb file takes up 4kb of space on most modern HDD. (check block size, older hdd typically have larger blocks -- doubt they are still running today.)
if you don't care bout 100,000 face pics, delete them for old players. (date on image file may tell you where that horizon is safe to cut)
you can set it so it only creates a face pic on demand... that will save a tone of space. if you haven't clicked them, it's not generated.
the type of data you save can be slimmed down -- some thigns can be rebuilt... e.g. you can disable those thigns that can be rebuilt solely from a boxscore as needed.
mil stuff-- turn off completely? or same personal choices you used for MLB etc.
deleting players doesnt' do anything to size.. they remain in dB, unless purged, see below - don't do it.
with 100 years i don't think a purge will really make much of a difference, and that will 100% screw up all th old newspaper links to player profiles. it'll reak okay, but clicks will take yo to the new player with that playerid...
(playerid is key field, it's auto-incremented and must stay in order... so it re-organizes after a "purge" of the dB. same players, new playerid's across board inevitable. and not a huge savings in space... 10,000players is nothing, for exmaple. it's text in a dB. Mbytes, not Gbytes. unlike above it's part of a larger contigous file, so it's not 1kb taking up 4kb situation)
So, before making any choices i'd perus which directories are the hogs... prbably news and messages stuff. you don't have to get rid f it all, but it might require you to unzip it when you want ot read it or use it.
almanac? not experienced on available options.. if each time you make it it is a new copy and "whole" you can delete old copies.. ?? have to read screen and apply some critical thought in that realm...
zipping/rar'ing is always an option for somethign that sits unused on the side.
I made a suggestion about he game archiving this stuff or somethign similar on more than one occasion. another thread won't hurt in the suggestions forum
programs can read from an archive and only uncompress specific files as needed and it wouldn't even be noticeable to a human's eye as far as load times. not only that it'll be way less wear'n'tear on hdd/ssd i bet. i've never seen a game so write/read intense in my life. it cuases larger and constant queueing than a torrent download.
not a great parralel becaue i don't keep much outside of boxscores and do not make an almanac, face pics are disabled -- ~55years it's upto 1.2GB ... 100gb? holy %$#@! what are you doing, lol... kidding a bit.. 95% joking. really 100gb? lol
if it were a "full" world with all international leagues i'd wager 5gb or so. so you shoudl have a goal of ~15-20GB or less.. i think that'd be easily possible and retain all that you want to keep. (plus any size of 1 almanac? extra?)