I actually like that, and it provides a certain grim poetic justice to the ending we got. Radue was a decent enough person, but he was quite arrogant, and guys like him don't take humiliating defeat well. He accepts Federation assistance to save his people from extinction, but as soon as he no longer needs them, he chucks them out. Who knows, maybe with some judicious re-engineering, the shield and cloaking device can be run without depleting the ozone layer. End result, Aldea goes pure isolationist; the Federation gets its seven kids back (thanks to Wes, they were now more trouble than they were worth anyway), but loses out on tech that could have saved millions had it been available in the Dominion war. They don't even get the knowledge Radue originally offered as compensation.
It was really stupid for the Aldeans to insist on letting in the natural sunlight from their star - including the ultra violent ultrviolet rays - to heat and light their planet.
That mean they have to say close to their old orbit around their sun, and makes it almost infinitely easier for enemies to locate Aldea. I don't mean that it makes it mere millions of times easier for enemies to find Aldea, it makes it gazillions of times easier for enemies to find Aldea, and thus makes it gazillions of times more likely for enemies to actually find Aldea despite the cloak, using methods suggested in my post number 42 on page 3.
They should have put an artificial sun saelite in orbit around their planet to replace their sun. It would have many gigantic fusion generators to power many gigantic lamps aimed at the planet. Or possibly they would need several such sun stellites in different orbits.
And the planetary shield would cover the radius os psace byond the orbits of the sun satellites, and the planetary cloaks would extend beyondt he planetary shield..
If they did that, they could then use supergigantic warp engines to move Aldea to some location hundreds of light years from Epsilon Mynos, and several light years from the nearest star, where nobody would have any reason to search for them. Or possibly travel hundreds of thousands or millions of light years into the void between galaxies.
And I think that must have been what the Aldeans did do for thousnds of years until their artificial sun satellites failed and they couldn't repair them. Then the Aldeans moved back into their planet's vacent orbit around Epsilon Mynos and used the sunlight from their star to warm and light their planet. And when the ozone layer was damaged the ultraviolet rays caused their fertillity problems.
That is the only way I can think of for Aldea to be undiscovered for thousands of years.
The Aldeans could put another, additional planetary shield around Aldea, one designed to light most wavelengths of harmless light in but block most of the ultraviolet light, letting in just the necessary amount..
Or they could make ozone out of oxygen and shoot it up to the ozone layer to replace the deplited ozone.