ednksu gets it
If you lost someone that you loved as much as Ted loved the mother (and I think he did), it makes sense that he would gravitate towards Robin and play up their story because he was trying to justify moving on to his kids. So, there would be a bias towards their relationship in the narrative because it was a way of justifying their history so he would get their approval.
2030 puts Ted somewhere in his late 40's, so he wasn't going to be alone forever. He just loved two women in his life at extreme levels, and he lost one too young. The other one always put her career first and lamented the choices she made (and the ensuing loneliness), and her inability to make it work with Ted was more a matter of timing than anything. It just so happened that the timing worked later in life, and Robin was able to make it work with, from her perspective, the one that got away.
The mother loved that Max guy to the point where they probably would have married, but he died young. The writers absolutely put that in there so the viewers would assume she told Ted that story and would tell him to be happy and find love again. They also started dropping literal references to Robin realizing that she should have married Ted even on the day of her wedding. It makes sense that they would ulitmately find their way to each other when the timing was right.
For everyone saying the ending with Robin cheapens the relationship, Ted waited six years and raised his kids on his own. The guy deserves to find happiness like the mother deserved to find Ted after her first love died. My assumption is that he re-stole the horn; it wasn't something he kept.
So, yeah, I'm good with it now. Was it a long con designed to keep you hanging on? Yes. But we saw how he met her, based on flash forwards and how he spoke about her, he loved her more than Robin, but in the end, Robin was the right person to help him find happiness again.