Greatest team of all time?

The 2015 RWC-winning All Blacks are being described as the greatest rugby team of all time. No question they are a great team but best ever? 
I reckon that's a very big call. They are certainly up there with the best but I'm not convinced they're a better team than Hennie Muller's 1951/52 Springboks, Willie-John McBride's 1974 British Lions or Sean Fitzpatrick's 1996 All Blacks.
I don't think it's possible or fair to compare players from different eras because the game has evolved so dramatically and continues to evolve. Hennie Muller's 1951/52 Springboks would probably lose 100-0 to Richie McCaw's 2015 All Blacks because the game has since become professional while players are so much bigger today than they used to be back in the first half of the 20th century. The only way one can compare teams from different eras is to examine the extent by which those teams dominated their contemporaries. 
If one uses the domination of one's contemporaries as the yardstick then the 2015 All Blacks fail in a direct comparison with their 1996 predecessors. There's no doubt that Sean Fitzpatrick's 1996 All Blacks - the first (and only) New Zealand team to win a series in South Africa - were significantly superior to the Springboks while Richie McCaw's team were only marginally so . . . 2 points to be precise.
And what of Willie-John McBride's 1974 Lions who absolutely smashed the Springboks and were only prevented from scoring an unprecedented 4-0 series clean sweep by some dodgy refereeing from Max Baise in the 4th test?
And let's not forget the great Springbok team that won the a European Grand Slam under Hennie Muller. Springbok legends in almost every position, they notched the third of  four Grand Slam tours before New Zealand or Australia had managed even one.
Here's a reminder of the teams I consider to be contenders for the title of Greatest of All Time:
1951/52 Springboks 15 Johnny Buchler14 Paul Johnstone13 Ryk van Schoor12 Tjol Lategan11 Chum Ochse10 Hansie Brewis9. Fonnie du Toit8. Hennie Muller (capt)7. Stephen Fry6. Basie van Wyk5. Willm Barnard / Ernst Dinkelmann4. Salty du Rand3. Okay Geffin2. Willem Delport1. Chris Koch
1974 British Lions15 JPR Williams14 Billy Steele / Andy Irvine13 Di'ck Milliken12 Ian McGeechan11 JJ Williams10 Phil Bennett9. Gareth Edwards8. Mervyn Davis7. Roger Uttley6. Fergus Slattery5. Gordon Brown4. Willie-John McBride (capt)3. Fran Cotton2. Bobby Windsor1. Ian McLauchlin
1996 All Blacks15 Christian Cullen14 Jeff Wilson13 Frank Bunce12 Walter Little11 Glenn Osborne10 Andrew Mehrtens / Simon Culhane9. Justin Marshall8. Zinzan Brooke7. Josh Kronfeld6. Michael Jones5. Robin Brooke4. Ian Jones3. Olo Brown2. Sean Fitzpatrick (capt)1. Craig Dowd
2015 All Blacks15 Ben Smith14 Nehe Milner-Skudder13 Conrad Smith / Sonny-Bill Williams12 Ma'a Nonu11 Julian Savea10 Dan Carter9. Aaron Smith8. Kieran Read7. Richi McCaw (capt)6. Jerome Kaino5. Sam Whitelock4. Brodie Retallick3. Owen Franks / Charlie Faumuina2. Dane Coles1. Tony Woodc'ock / Wyatt Crockett / Joe Moody
Richie McCaw's 2015 All Blacks must rank as one of the greatest teams of all time, but to call them the greatest ever is something of an insult to the truly great teams in rugby's history.

2015 All blacks team would beat all the teams above easily in it's prime. There's really no doubt about it. It's the greatest team of all time. 

Jerome, are you basing that on the extent to which they've dominated their contemporaries? If not, please read my post again and try to understand the point I'm making regarding comparisons between teams from different eras. 
By way of example, I think the 1996 All Blacks were a greater team than the 2015 All Blacks . . . even though the 2015 All Blacks would beat them in a match-up if all players were at their prime. That's just evolution. You may as well say that Justin Gatlin is a greater sprinter than Jesse Owens or Michael Clarke is a be tter bat than Sir Don Bradman. Many would disagree.

Its almost impossible to make that call given how much the game has changed over the decades  

Got given the Rwc on a platter by Craig Joubert. Won this Rwc on a dubious call against a Bok side playing weird rugby. Won the test in SA tbrough a cheat by mcaaaw. Won a number of other tests sgainst Boks via ref assistance. No they are not the greatest ever nor even great. Good side possibly. Greatest ever - HAHAHAHAHAHAHA sidesllitting stuff!!"""

 "Sidesllitting"?Please read my other post re spelling etc Hasbeeno and commence attending Night School immediately. 

 Greatest team ever, no doubt about that. Look at their record since 2011.Yes, there have been a few changes but the nucleus of the team remained intact and their domination I believe is unparalleled. The only reason the ABs haven't won more series in SA since 1996 by the way is because they no longer have them!

 Rooie seeing as how instead of tours we have the Tri-nats and now 4-nats perhaps the 2 away wins per season scored in the tri-nats would have to suffice for the ABs .Dont you ever shut the Fark up beansh!t head ? When grown ups are conversing just stay in your corner with your poin ty head in your pointy hat you mong .