A lot of people buggered off for the Day Watch? I don't know about 'a lot'. All we know about are Cpl "Mayonnaise" Quirke and Sgt Winsborough Knock.
(Both of them are mentioned throughout the series, and in "Night Watch" we see how it happens).
Yes, the Day Watch and Night Watch are amalgamated at some point during (or just after) MAA. And yes, in G!G! we learn that the Day Watch guards tend to look down on the Night Watch.
Ah, now I remember Quirke! I was trying to remember who the character was, but all I could think of was some vaguely snot-nosed twit of a copper that would have been played by either Hugh Laurie or Tim McInnerny.
Vetinari basically decimated an already threadbare Watch as a whole when he allowed the Guilds to "police" their associated crimes. One can assume that the Day Watch of GG is as lightly-manned, demoralized and ineffectual as the Night Watch. The only people the Day Watch can feel superior to is the Night Watch.
Fred and Nobby are the cliched "career holdouts" you also see in police departments (or at least in police procedural books and shows). They're the lifers, the ones who have been there so long that no one has the heart to fire them. They're dinosaurs, but every now and then they contribute something useful.
I was under the impression that the Day Watch wasn't as undermanned or underfunded as the Night Watch, albeit to a small degree, simply because they didn't rock the boat as much. I mean, not that Nobbs or Colon or a pre-
Guards! Guards! Vimes would do so, but still...or else there was a vague sense of prestige to the Day Watch compared to the Night Watch. Keep in mind, it's been over a decade, I think, since I've read the novels of
Guards! Guards! and
Men at Arms, so I could be mistaken.
I'd imagine Jack Frost from
A Touch of Frost would be a more successful and competent version of that sort of career holdout you mentioned, raisindot. I don't watch police procedurals per se, but my mother loves them. I'm actually struggling to name any real examples from these shows, partly because the characters I can think of actually take a more proactive and central role, like, for example, the members of UCOS from
New Tricks, or Morse from the original
Morse series (and honestly, I actually prefer Shaun Evans as the young Morse in
Endeavour compared to John Thaw in the original series: Morse in the original series is pretty bad towards poor Lewis, and I actually prefer the dynamic Lewis and Hathaway have in
Lewis).
I think another thing that should be brought up with Nobby and Colon is that they're a classic double act. I've been a fan of these partly thanks to
Doctor Who, with many of the stories written by Robert Holmes having wonderful double acts. Garron and Unstoffe in
The Ribos Operation, Irongron and Bloodaxe from
The Time Warrior, Spandrell and Engin in
The Deadly Assassin, Sabalom Glitz and Dibber in
The Mysterious Planet, Henry Gordon Jago and Professor Litefoot from
The Talons of Weng-Chiang...I could go on.