Artists whose earliest and latest works show no discernible difference.

Also, Status Quo's debut album was different than what they would do later, but from their second album in 1970 and onwards, there was no discernible difference into the mid 90s.

Status Quo, though, definitely. But a lot of 'rock' bands didn't change much. Is there that much evolution in AC/DC or Lynyrd Skynyrd?

Chic?

One could argue that the Buzzcocks, one of the best of the original UK punk bands,
changed very little from their early singles until today. I admired that in a way as it seems they are the only band who didn't evolve (unlike the Damned, the Clash, Siouxsie, Slits et al) but were still great . . . unlike all the bands that didn't evolve much that all sucked (Sham 69, Chelsea, 999, etc).

The Archies?

Mission Of Burma? (maybe not 3 albums per se . . .)

...and still sounded the same.

You don't think there was development from the raw punk thrash of Another Music In A Different Kitchen through the pop-punk of Love Bites to the more experimental A Different Kind Of Tension?

Admittedly the reincarnated version of the band does seem to have got itself stuck to some extent in a stylistic rut somewhere around 1978 (so it's arguably true that their "earliest and latest works show no discernible difference" but I don't think it's true to suggest that they haven't been anywhere different in between.

". . . unlike all the bands that didn't evolve much that all sucked (Sham 69, Chelsea, 999, etc)."

I haven't seen the latest incarnation of Sham 69, but I saw one in the mid '90's that had a sax player, several female backing vocalists and was in every possible respect absolutely nothing whatsoever like the original incarnation.... well, except in the one crucial respect that they still totally and utterly sucked (I specifically remember one awful dirge that seemed to go on and on for at least 10 minutes of which the entire lyrical content seemed to consist of "God save The Rainbow Warrior" repeated over and over again ad nauseam!).

Chelsea: I agree completely and unreservedly in every respect.

999 I'd certainly agree that their "earliest and latest works show no discernible difference"; but again I'd be inclined to argue that they have been to other places in between - and I certainly wouldn't agree that all of it sucked; indeed some of the stuff on 999, Separates and The Biggest Prizer In Sport is positively great (and I know a certain NYC-based ILM-er who'd put a spirited argument in defence of Concrete too).

You don't think there was development from the raw punk thrash of Another Music In A Different Kitchen through the pop-punk of Love Bites to the more experimental A Different Kind Of Tension?

I think the Buzzcocks altered the ratio of raw energy to pop to experimentalism
from album to album, but essentially all three elements were always in evidence -
witness:

Fast Cars -> Nostalgia -> Mad Mad Judy
Moving Away From The Pulsebeat -> ESP -> Hollow Inside
I Don't Mind -> Ever Fallen In Love -> You Say You Don't Love Me

Probably not the best examples, and yeah, each album has a different feel that
you could call development, but given the fact that they've obviously retrogressed,
it's easy to call it playing with the recipe a bit, not development in the sense of
their peers such as the Clash or Siouxsie, who really changed in almost
unrecognizable ways over three albums. Not that I care either; I love the Buzzcocks
like mad to this day!

I haven't seen the latest incarnation of Sham 69, but I saw one in the mid '90's that had a sax player, several female backing vocalists and was in every possible respect absolutely nothing whatsoever like the original incarnation.... well, except in the one crucial respect that they still totally and utterly sucked (I specifically remember one awful dirge that seemed to go on and on for at least 10 minutes of which the entire lyrical content seemed to consist of "God save The Rainbow Warrior" repeated over and over again ad nauseam!).

I had no idea! (Though I do recall Jimmy Pursey's abysmal "Alien Orphan" thing.)
I stand corrected, though in my defense it's fair to say that most people could
immediately make the decision not to inspect Sham 69 too closely!

999 I'd certainly agree that their "earliest and latest works show no discernible difference"; but again I'd be inclined to argue that they have been to other places in between - and I certainly wouldn't agree that all of it sucked; indeed some of the stuff on 999, Separates and The Biggest Prizer In Sport is positively great (and I know a certain NYC-based ILM-er who'd put a spirited argument in defence of Concrete too).

I was a bit harsh on 999 - they had their moments for sure, but I still maintain they weren't very diverse and didn't develop all that much.