The Lucerne was actually the last model made on the venerable H platform, on which the LeSabre,
Pontiac Bonneville, and
Olds Eighty-Eight had previously been based. The styling of the Lucerne was too close to the last W-body Impalas (2006-2016) for my taste. The first few years of the LaCrosse were also on the W platform, which had been in use since 1988 (Chevy Lumina, Monte Carlo, and Impala;
Pontiac Gran Prix;
Olds Cutlass Supreme and Intrigue; Buick Regal, Century, and LaCrosse). The later LaCrosse was based on the Epsilon II Extended platform, which also included the
Cadillac XTS and the last iteration of the Chevy Impala, which was a longer wheelbase version of the Epsilon II platform, on which the last iterations of the Chevy Malibu and Buick Regal were built. While the Regal was a direct re-badging of an Opel Vectra, the later LaCrosse had no Opel counterpart. In that transition, the LaCrosse made the leap from a larger midsize to a full size car. The Epsilon II platform effectively replaced the aging H platform, while the shorter Epsilon I replaced both the aforementioned W platform, as well as the G platform on which the
Olds Aurora and the final iteration of the Buick Riviera (1995-1999) were built. The Verano, on the other hand, was built on the Delta II platform, which it shared with the Chevy Cruze and Opel/Holden/Vauxhall Astra. These car platforms were essentially lost to GM when they sold the Opel/Vauxhall division off to Stellantis Group.