He did that or simply use the situation to make lulu stronger, just look that at the 1st generation of possible successors:
1st : average Joe and a princess nobody ( possible they were arise having everything and without the need to competed for anything )
Now look at the 2nd generation we have Cornelia, Schniezel and Clovis they have older siblings and have standard to aspire and surpass but here is were it gets inserting.
Cornelia got a Euphemia which she love a lot and make her weak or vulnerable, She was still strong and a good candidate for the throne but she also posses a fatal weakness
Schniezel end up being an excellent heir he is cool headed and is always looking for a new advantage
Clovis end up being FABULOUS