The Cadillac CT6 debuted in New York and will lead a revamp if the brand's product portfolio.

With Cadillac planning to introduce eight all-new models by 2020 – five of them targeting all new product segments – several existing vehicles will be heading off to the scrap heap, according to the luxury maker’s global boss.

The realignment of the Caddy product portfolio means there will be “no direct successor” to the current ATS, CTS or XTS models, Cadillac President Johan de Nysschen told TheDetroitBureau.com.

But, the South African-born executive explained, “There will be new models that better meet the requirements of the market and allow Cadillac to better cover the various market segments than is the case today.”

De Nysschen stressed that the three models “will not be discontinued,” but will run out their “normal seven-year lifecycles.” Only then will they be replaced by all-new products based on what he termed “Cadillac-specific architecture.”

The XTS is likely the next model to be phased out as part of the brand's line-up makeover in a few years.

The Cadillac XTS is the oldest of the three, launched in mid-2012 as a 2013 model. The ATS came on very shortly afterwards. Doing the basic math means the all-new replacements would likely appear at the very end of the decade. The third-generation CTS, meanwhile, was launched as a 2014 model, so the replacement product wouldn’t follow until around the 2021 model-year.

How much different the new ATS and CTS replacements will be remains to be seen. Ironically, both received strong praise from reviewers – the smaller sedan winning kudos as North American Car of the Year – but have not generated nearly the sales success anticipated. Almost certainly, Caddy will rename the successor products, in line with the new alphanumeric nomenclature introduced with this month’s debut of the all-new Cadillac CT6 flagship sedan.

One thing is clear: the two new models will retain the basic drivetrain layout of the current ATS and CTS in that, “It’s envisaged that all future Cadillac sedan architectures will be RWD, with AWD capability,” de Nysschen explained.

That would indicate the most dramatic change will occur once a replacement for the XTS comes to market. The big sedan has been seen, almost from word one, as the misfit in the Cadillac line-up because it is a front-drive product that also can be ordered in all-wheel-drive.

The New York Auto Show marked “the first step of this rejuvenation and expansion” of the Cadillac brand with the debut of the CT6. It will serve as the maker’s flagship for at least a few years. An even more lavish model – expected to be designated either the CT8 or CT9 – is due around the end of the decade, according to de Nysschen.

Also in the works are two all-new crossover-utility vehicles, as well as replacements for the current SRX and Escalade models. Caddy may eventually get new coupe, sports car and convertible models, as well, though those are considered lower priorities in the $8 billion brand revitalization effort.

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Part of the challenge, said de Nysschen, is to “avoid such overlaps” as occurred with the debut of the ATS which was nearly the same size as the second-generation CTS.  The XTS is another “tweener” car that doesn’t readily fall into a distinct niche, at least from a size perspective. It was originally seen as becoming the Cadillac flagship, but it quickly became apparent it wasn’t up to that role.

Another model expected to fall out of the Cadillac line-up will be the Cadillac ELR. The dedicated hybrid was a visual standout but its Chevrolet Volt-derived drivetrain was far too anemic for luxury buyers and sales have been miniscule, at best.

(Click Here for details the CT6 hybrid debuting in Shanghai.)

Whether it will continue for a full seven years following its late 2013 debut remains to be seen. But de Nysschen told TheDetroitBureau.com it does not fit the brand mission any longer.

That’s not to say Cadillac is walking away from battery power. With the 54.5 mpg Corporate Average Fuel Economy standard looming for 2025, Caddy has to find ways to significantly boost fuel efficiency. But it will take a different approach going forward.

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The first step will be announced at the Shanghai Motor Show this month with the unveiling of a plug-in version of the new CT6. According to de Nysschen, there will be plug-based drivelines added for virtually every new Cadillac model by decade’s end.

That’s in line with the plans announced by rivals, such as Mercedes-Benz, which plans to add 10 plug-ins by 2017.