Argyle led 2-0 early in the second period before Palace scored three times in five minutes to set up victory.
The hosts, who won League One last season, made nine changes and dominated the first 55 minutes of the game.
"I'd like to say we were surprised by how good Plymouth were, but we weren't," Hodgson told BBC Sport.
"We knew they were very good and made it clear to the players that this is a good team you're playing.
"We thought when they made changes, 'Maybe we'll be lucky, maybe the ones they've brought in won't be as good,' but they were."
The trio all had input in Palace's four goals as Argyle missed out on a third-round tie in the League Cup for the first time since 2007.
But Hodgson was full of praise for Schumacher, who is in just his second full season in charge at Argyle and has won many plaudits for his side.
"I think he's done a magnificent job and you see that on the field of play because that team's well-organised, that team's well-coached, that team's well-prepared in every respect, physically, mentally, tactically.
"In that respect he's done a very good job, and also I think they've got some very good players, so that's the winning combination.
"I've got to say I think they'll win many, many matches in the Championship, because if they can play at that level as they did tonight against us, then I'm pretty certain they'll find Championship teams they can beat without too much difficulty."
The loss was the third heart-breaking one for Argyle in as many games after conceding last-minute goals to lose at home to Southampton and away at Birmingham City.
"That's the thing I'm learning about the Championship, and obviously up against Premier League opposition tonight, is that the little small mistakes, you get punished," Schumacher said after the loss.
"But we've just got to keep believing in what we're doing and hopefully the chances we create will be enough to give us chances to win games."