In addition to the reissues @Sbank mentioned on vinyl-- high quality at a reasonable price, there are current bands- Snarky Puppy out of Northern Texas is a jazz collective that ought to scratch your big band itch. There are similar collectives in the UK too, Maisha, for example, which channels spiritual jazz. They did a direct to disc record a few years ago with Gary Bartz, who was one of the original players from the era. I don't know what format you are collecting --CD? but that may be part of the problem since for now, it is considered a dying medium. (They said that about vinyl too, remember?)
I'm all about discovery, research, "surfing" music-- lots of it is older stuff. I found a groove in the post-bop era from the early '70s-- spiritual and soul jazz--may not be your thing, but the point is, there's a ton of music I haven't explored that is out there. And given the relatively low price demanded for most CDs these days (if that's your thing), you can take some risks.
There's also this thing called "Bandcamp" which is a site where bands/labels that don't necessarily have major distribution sell directly- you can sample the music and buy in a few different formats.
Every once in a while I'll fire up a more well known performer, like Art Pepper, but an awful lot of what I've bought in the last ten years is small/private label stuff. Some of it is more avant garde than the acts you mention, but I've gradually developed a taste for less predictable stuff--
As I mentioned elsewhere, Alice Coltrane's Ptah the El Daoud has been out of print on vinyl since 1974. It is finally being reissued on LP though has been available on CD.
There are plenty of resources, from threads here and groups on Facebook to blogs. Once you get started, it becomes an adventure- you hear an album you like and really appreciate one or another of the supporting players- you look that person up and find a wealth of other albums on which they are featured or appeared as sidemen.
Good hunting!