The more things change in the TV news business, the more they remain the same, if two milestones that happened Monday night are any indication.

On CBS, Scott Pelley assumed an anchor chair vacated in May by Katie Couric; on PBS, a newscast once called the “MacNeil Lehrer Report” aired without its former hosts, Robert MacNeil or Jim Lehrer, for the first time in 36 years.

MacNeil left the show in 2005 and Lehrer announced his retirement in May.

In his “CBS Evening News” debut, the white-haired, angular Pelley was smooth and solid, if not exactly exploding with charisma.

Robert Thompson, the founding director of the Bleier Center for Television and Popular Culture at Syracuse University in New York, said by phone that the choice of Pelley was an “old-school decision.”

“And it was a good idea,” he said.

After Tom Brokaw, Peter Jennings and Dan Rather all vacated their anchor positions for different reasons years ago, Thompson said, there was an effort to “get younger audiences.”

“When all the smoke and mirrors had cleared; if you look at a network evening news show today, it pretty much looks exactly as it did 30 years ago,” Thompson said. “The format is not all that much different.”

When Couric came to CBS in 2006, she aspired to make the newscast less formal, with more interview segments. But viewers were not enamored of the approach.

Thompson said Couric should not be judged too harshly.

“(When she came to the network), CBS News had had a long tradition being in last place,” he said. “The CBS morning show and the ‘CBS Evening News’ had been struggling a long time and all the king’s horses and all the king’s men have yet to figure out a way to put it all together again.”

It may take awhile to see whether the addition of Pelley has any effect.

Pelley, who resembles in voice and visage a younger Bob Schieffer, seems cut from the same cloth as Walter Cronkite (or, at least, assembled from similar remnants).

WANE-TV news director Ted Linn said Pelley has stirred up a level of excitement among local viewers that even he has found surprising.

“This Pelley thing just might work, and if you had asked me last week, I might not have said that,” he said. “I didn’t know who they could put in there short of Christ (who could make much of a difference).”

But Pelley makes his debut in a world where no single media figure will again command the trust and wield the influence of Cronkite.

“There will never be another Walter Cronkite,” said Indiana’s NewsCenter President and General Manager Jerry Giesler. “The 24-hour news channels ended that era. Now, 6:30 at night is just another half hour in the day. It is not a nightly watershed moment where the tablets come down from the mountain carried by Cronkite. That’s just the way it is. People don’t buy it anymore when you tell them nothing is going to change for another 18 hours or so.”

Where the Pelley-fronted newscast featured mostly gray-haired male correspondents and pretty young female ones, the new PBS “NewsHour” was staffed by a multicultural and multigenerational cast of co-anchors, an arrangement described by MacNeil on the website as a “team of colleagues.”

“Instead of shopping for a new bright star,” MacNeil said, “(Lehrer has) encouraged the emergence of a team of colleagues who increasingly share the anchor duties, as well as field reporting. Now the ‘NewsHour’ works like a repertory company in the theater, with different correspondents coming forward to take the lead part, or share it with another, on different nights.”

The new PBS “NewsHour” is just as much of a well-oiled machine as the newest version of the “CBS Nightly News,” but “NewsHour” has a quieter and more deliberate pace and a much plainer set design.

The amount of time that “NewsHour” spends on each story would severely tax the patience of many 20-somethings. But Thompson said 20-somethings may never have watched the nightly news in great numbers and it is a not a group that is really worth going after.

“You tend to alienate the audience you’ve got left, and they are not chopped liver,” he said.

As much as cable and the Internet have siphoned viewers away from network news, Thompson said, prime-time national newscasts still garner much higher ratings than comparable cable programs.

“It’s not worth trying to reinvent it,” he said.

Thompson said he doesn’t foresee a day coming when the big three networks decide nightly newscasts are no longer worth doing. There will probably always be a place for network news, Thompson said.

And there will probably always be a place for a show like PBS “NewsHour,” Linn said.

“It represents a real alternative to the in-your-face approach,” he said.

Thompson, who has been a talking head on most news shows, said he prefers to appear on PBS “NewsHour.”

“It has always given me the opportunity to say something more intelligent, instead of just trying to interrupt whoever is talking at the time,” he said.