I'm not sure exactly how to phrase this classroom, but: if Laschet is around where Merkel is (or even very slightly to the left, which is what a lot of the sources sources I've looked at so sad), what is the point of CDU? Just a nearly non-ideological, sort-of party of power? Wouldn't this be highly frustrating for any voter who's even a bit self-consciously conservative?
I'm not German, so I'm not going to talk about anything candidate or ideology specific. However, I do think it is important to mention the Union's perceived electoral situation, cause that also explains why someone who might disagree with some of their policies still happily votes CxU.
A - Tradition. Simply put, the Union has a long-lasting brand in Western Germany as the electoral vehicle of Conservatives. There are always a lot of people who have been voting for a large party for most of their life, and loyalty is something hard to break once built. Contrast this to the East where the voting population is comparatively newer to German politics. The fundamental differences have led to people expecting something different from their Conservative party than the Union is offering - as seen by other Eastern European parties of significant size that align with their nation's political Right.
B - If it ain't broken don't fix it. Merkel has led the Union for most of the 21st Century at this point, and I can't point to any major thing that her govt has bungled. The crises that emerged were all navigated in a calculated manner that may not have been the best approach, but ones that had little chance of blowback in Germany. In this regard, there will always be incumbency voters, no matter the Democracy. If the govt has been in power for long enough the reflexive desire to see change for the sake of change is replaced by one to maintain the present govt, since the unknown may be worse than the known.
C - Who else can? If you are walking into a polling place this year, and your identity aligns with the German Right, most of your consideration will go to the Union, AfD, and FDP. The issue now is whether you should vote for the party that may not peruse all of the policies you prefer, but will pursue some and be in govt, or the party that will just harass the former from the sidelines. Spoiler, most people are not ideologues and married a dozens of a parties proposals. The silent majority of those less-caring about politics if you will. The minority that have committed their party or its platform to their identity are the activists. They tend to block out the former though because devotees have the urge to post on social media or chatrooms, speak in the press, rally or protest, donate to auxiliary organizations, and maybe even join a youth wing or organizational group. A good chunk of those who care less about ideologies and the political game will check the box of the bigger party, since that is the one with the best opportunity to legislate on their behalf.
Many of these same rules preserve Parties of Power around the globe, no matter their specific proposals or leadership. See Likud, the Swedish Social Democrats, the LDP, and a few others.
