Attribution modeling in marketing is highly complex and challenging, often more so than tasks like rock climbing, according to experts such as Buddy Marshburn, a data engineering manager at Loom. The debate between last-touch and multi-touch attribution models remains unresolved, and many suggest focusing on aggregating all customer touchpoints to improve business decisions. Boris Jabes, CEO of Census, emphasizes integrating product, marketing, and sales activities to enhance understanding and decision-making. The intricacies of attribution modeling include dealing with unclean data and accurately allocating ad spend, as highlighted by Jarry Ahmad from Uber, who points out the importance of collaboration among stakeholders to define metrics and achieve accuracy. Incrementality testing is recommended to assess the true impact of marketing spend, as evidenced by eBay's 2012 study showing limited effect of search ads on sales. With attribution modeling's current limitations, there is a shift towards marketing-mix modeling, a more holistic approach that considers non-click-based marketing strategies and employs techniques like multi-linear regression to evaluate diverse factors affecting sales and ROI.