I cracked recently and went out and bought volume 1 of the trade in a desperate attempt to understand what was going on.
The current story made you buy a trade collection of the earlier material? What
insanity is Rebellion up to!

Joking aside, it is obviously a big problem when stories are spread across such a length of time, and generally their earlier parts are lost in the prog mountain. More detailed recapping would be nice, but ultimately it comes down to a choice between running longer more complex stories with large casts, or just simpler continuity-free tales. I know I personally would never want to see an exclusive focus on the latter.
Taking the Red Seas as an example - it's a large-cast team story that's been running since 2002, with a core plot running in the background right the way through its 60-or-so episodes. That's very roughly the same page length as Watchmen, but spread over 8 years. It's not surprising people coming new to it, or trying to remember exactly what happened when Jack seized Eerebus, are having problems.
By contrast 'original' Rogue Trooper, the very simplest of small-cast stories, also ran over 8 years but racked up about
800 pages between the Quartz Zone Massacre and The Hit. No-one had any problems remembering what was going on in Nu-Earth/Horst era Rogue, but wonderful as the early stuff was do we
really want a return to stories like that today?
Best to consult the Wiki and the trades out of the library.