doubt it's anything sinister.

they're basically spinning off the dogs from the growth plays so that their valuations will align accordingly. Next move will probably be to sell off some of the lower performing businesses.

Disney would like to do something similar.

Strictly my cynical personal opinion:
CEOs look at tech stock appreciation and get jealous since tech can achieve huge gains in stock price while losing money. In the world of publicly traded companies, it's all about growth and not necessarily about profits. Kellogg is going to try to group their "trendy" products together and see if then can achieve a higher stock price based on some speculative investors. They will be generating the same growth, but now on $1 billion of expenditures compared to $10 billion previously (for example). Their previous 1% growth on $10B is now 10% growth on $1B, and investors rush in to buy and raise the stock price. The other $9 billion company goes from 1% growth to 0% growth and stock price is mostly unchanged. Overall value of the combined companies goes up, even though they haven't generated any additional growth or profit. Bankruptcy protections only make it worse by encouraging companies to take on significant risk in the pursuit of growth.

Was around when Dr Pepper de-merged from Cadbury, then Cadbury was acquired by Kraft, sho then split the business into a couple of companies, all under the auspices of unlocking value.

It was, as agnerd and Diggity pointed out, driven by market pressures. The markets are very nuanced and will sort of irrationally hold CEOs to account and pressure them to achieve targets that may not actually be in the best interest of the overall business.

Combine that with consultants / advisors making tons off these sorts of splits and you get things like this. The logical, and in my opinion correct, thinking is that these business should indeed be able to unlock any "trapped" value without this sort of transaction.

Lots of companies get too big to where capital allocation decisions are made at an executive level resulting in under/over investment in promising/diminishing parts of the business because they don't fully understand the product/service at the ground level. Especially big, multi-national conglomerates.

As someone that has worked with a number of divestures at different large companies, I've seen it first hand. Capital decisions being made by a bunch of MBAs at corporate that don't fully understand the product based on what looks good on a PowerPoint and financial model.

On one divestiture I saw, there was a technology change and they missed the boat because they underinvested in R&D for upgrading the product. They were the market leader, but it was an older legacy product that wasn't as sexy/tech-heavy as other products in the conglomerate's portfolio. The immediate management team wasn't in charge of the R&D team because it was managed by a more centralized R&D team which supposedly meant they would have greater access to resources and specialists, but actually resulted in an R&D team that was further away from employees who actually understood the key functionality of the product. They closed down a small facility because upper management thought it looked good on a PowerPoint as a cost savings that could theoretically be served from a nearby facility, but that small facility was an outlet to a key customer and that key customer stopped buying the product from all facilities over time. Ask the management teams for an income state and balance sheet of the carved-out business, and they've never had to manage a balance sheet and only manage decent chunk of the income statements. The carve-out's management team was a lot less entrepreneurial than a normal c-suite team, largely because they've spent their entire working life in a big conglomerate surrounded by lots of resources. And on and on across every function of the business. Lots of problems from too much consolidation.

your third paragraph is a perfect example of why breakups are sometimes needed