First of all, there is no viable way to actually use conscripts. Sending them overseas to die over a patch of dirt is a really bad move, as the Vietnam war has shown. Europe doesn't really want to invade anyone, so you're left with defense. So who's going to invade? The only foe even worth considering is Russia - and NATO's combined professional armies are more than a match for them. Not to mention that there are thousands of kilometers between Russia and the country considering conscription.
Second, it'd actually be a massive burden. The army suddenly has to train a bunch of unmotivated teenager every single year, which in reality ends up being a LARP session in a local forest. This drains a huge amount of resources from the professional soldiers. And all those conscripts will not contribute anything meaningful to the economy while doing so.
Sure, it might make sense if you are bordering Russia, but anything further west just isn't going to happen.