Well, that begs another question. If cricketing standards have declined, then how good do you think Australia and South Africa are? How good is the guy in your avatar?
They are good, the two best Test teams in the world IMO. Much better than the opposition they are playing at the moment
I do think we're living in a batting era, but I think cricket is still a contest between bat and ball & those players with high averages are very good batsmen.
There's no doubting that batsman like Ponting, Dravid and Kallis are fine cricketers. But do you really think that in an era that wasn't so batsman friendly that Mohammad Yousuf, Matthew Hayden and Kumar Sangakarra would all average over 50? Then there are the likes of Virender Sehwag, Mahela Jayawardene and Younis Khan who average just a touch under 50. Good batsman, all of them, and they have all been run machines in this decade. The real question is, are they really better than Mohammad Azharuddin, Gary Kirsten, Saeed Anwar, Martin Crowe and Conrad Hunte? Certainly their averages seem to suggest so, by a good 5+ points.
My judgement from two Tests is that Sri Lanka wouldn't have scored 550 runs if they'd batted first & NZ can't bat against pace regardless of the surface. Australia and South Africa simply have better batsmen than those two sides regardless of pitches, batting technology, smaller boundaries or any decline in bowling.
Facing the best team in the world, I doubt too many teams would score 550 runs TBH, especially not a team who have Prassana Jayawardene at #7 and Michael Vandort, Thilan Samaraweera and Chamara Silva in their side. New Zealand's batting deficiencies can be blamed on a number of things. No stable opening combination, one of our better batsman injured, and generally a lack of quality within our side at the moment.
Theoretically, an increase in the number of Tests played should lead to a decrease in players' averages, but in some cases it has led to an increase & those players are fine batsmen indeed. Batting still requires concentration and a high level of mental toughness & despite all the advancements in sport & coaching it's not something we see a lot of.
How should more Tests decrease players averages? Taking into consideration that now teams play Test cricket against Bangladesh and Zimbabwe, two very weak teams, and often opposition batsman really take advantage of this weakness. Nobody is doing it takes something special to score a truckload of Test runs, but in this era it has been much easier than almost any other decade in history due to a number of factors which people have listed throughout this thread.