I think you need to take all FCA's statements with a pinch of salt.
Their plans change week to week, merger with Renault, merger with PSA, 500 in mild hybrid, 500 in full EV only.
Ford tried the same trick when they dropped the original KA and ran without a city car while pushing the Fiesta.
Fiat, VAG, Renault, Citroen, Kia, Hyundai and all the rest were eager to fill the gap with Pandas, 500's, Mii, Up's, Citigos, Twingos, 107/8s, C1's, Picantos and i10's.
So what did Ford do?
Borrow a Panda/500 for their KA, then design their own (hideous) Ka later on.
That statement reads like Fiat are looking at the B class, the fiesta, Polo, ibiza, Fabia, i20, Clio, 208 etc and thinking we'll have a slice of that but we realise our cupboard is empty and our bank account is in the red and don't know what to do about it.
Will they really drop a class where they have a good slice of the market just to compete in another which is mainly made up of a range of brands sharing cost effective platforms?
Which brings us back to these mergers.
VAG, PSA, Kia/Hyundai and a few others have made platform sharing pretty profitable.
A full range of classes each with a budget, sporty/youthful, premium and snob brand choice in each based on a limited number of platforms, engines and running gear.
Fiat have the brands, but their platforms, engines and running gear are all over the place.
They can't sell the same cars (like the 500) in the US as in Europe without expensive platform mods, they have a mind boggling range of engines and platforms throughout their empire (most inherited when they've bought out other companies or like their Brazil arm, just doing their own thing) and don't really have the money to sort it all out, let alone modify their current range to meet the market demands of today (EV's, hybrids, active safety systems etc).
Without a merger it's likely they'll knockout warmed up versions of their current (and current pipeline) models for years or until they die a Punto's death while having to buy in systems at a great cost rather than develop their own.
With one, hopefully they'll get to share some tech for current demands, share development costs for new models across all brands and get some expertise in rationalising engines and platforms, something PSA have been eyeing VAG on for a while.