The Mets have the super young pitchers for success.

Still, the hardest lessons must be learned.

Just because you have those arms of gold doesn’t mean you are going to win a World Series ring.

Just because you’ve been to the World Series doesn’t mean you have a pass to get back to the postseason next season.

The Mets need to build a more sustainable team in 2016, which will mark the 30th year since their last World Series title.

The Royals beat the Mets in five games, utilizing the KC game, not the Mets game, to win their first World Series in 30 years Sunday night at Citi Field.

A number of scouts on Monday said they believe the Mets’ success simply is not sustainable.

If the Mets want to follow in the Royals’ 30-year footsteps, there is much work to be done. Life is going to get more difficult for the Mets next season because of their Amazin’ playoff run.

David Wright knows what’s ahead.

Of all the thousands of words that were said after the 7-2, 12-inning end -the-season loss, these 14 words were the most important.

“Next year I think we are going to have a target on our backs,’’ the Captain, said, already sounding the alarm for 2016.

The Mets aren’t sneaking up on anybody next season now that the Royals provided an easy-to-follow blueprint how to beat those gifted young arms. The smart teams will put more pressure on the Mets’ flimsy defense.

I’m not here to rain on the Mets’ parade. There was no parade.

And, after all, I did pick the Mets to win the NL pennant back in The Post’s preseason preview.

The value of these young arms cannot be overstated.

It’s best, though, to deal with reality right after euphoria leaves town.

Massive holes have to be patched, and the Mets have to hope these arms don’t suffer a postseason-run-into-November hangover like teams usually suffer.

Just look at the on-again, off-again World Series success of the Giants. It’s difficult for a pitching staff, especially the bullpen, to come back from such a lengthy season.

“The [Mets] pitching is there, but will it be worn down next season,’’ one scout said. “But the position guys are not there. They really need to clean up their defense, get a true shortstop, a big bat and they have an issue with their catcher’s arm.’’

Noted another scout: “The Mets have to get more athletic.’’

The Royals ran at will on the Mets. In catcher Travis d’Arnaud’s defense, the pitchers did not help him by keeping runners close.

Daniel Murphy and Yoenis Cespedes will move on and having young Dilson Herrera at second will improve the Mets’ defense, but will his bat play? Murphy’s pre-World Series hot streak will not be duplicated, so there has to be more balance to this offense.

As general manager Sandy Alderson walked out of Citi Field Sunday night, he seemed to be most upset by the fact the Mets collected just four hits in 12 innings of their final game.

Another problem, and this might be the biggest position question going into 2016: Is Wright going to be anything like the player he once was with his ongoing back issue?

Wright hit .208 in the World Series with one home run, four RBIs and eight total bases. With months of being able to monitor and come up with a better game plan for his spinal stenosis, Wright might be better in 2016. But the bottom line is the Mets have a 33-year-old third baseman with a bad back.

Over on the other corner, first baseman Lucas Duda provided two RBIs in the World Series and his poor throw Sunday night allowed the Royals to tie the game in the ninth.

The Mets had a storybook run but just once in their history have they been to the postseason back-to-back seasons, 1999-2000.

Yes, this was a memorable season but next season is going to be much more difficult from the first pitch.