Alternatively, look at American Open Wheel Racing. When CART split because Tony George was a money-grubbing, useless idiot, CART (and its successor CCWS) had the best cars, by far the higher quality drivers and racing, and IRL, which was restricted almost entirely to ovals, suffered. BUT it had the Indy 500, the one AOWR race which has global recognition value, which meant a lot to sponsors. The gulf in class was massively shown one year when Newman-Haas, a leading CART team, showed up to the "open entry" Indy 500 in the late 90s, and won it by a street with Juan Pablo Montoya. This gained a lot more exposure for the team than racing the CART season only could, and eventually big teams started defecting over to the IRL to compete under their rules despite the woefully obsolete cars and much less historic series. CART and CCWS contributed to its own demise with a dreadful business model, but eventually were subsumed into IRL a few years later, which abandoned some of its controversial calendar plans that had been a part of the split in the first place and appropriated some of the more prestigious CCWS races for itself (the Long Beach and Surfers' Paradise rounds in particular), reuniting AOWR but with massively reduced audiences and viewing figures.
RCS should have no intention of running the Giro in July against the Tour; the Giro is an institution in May. A "Big Tour in France" will never be the Tour de France, and ASO will likely be able to protect certain trademarks such as the jersey colours that have become so iconic in the sport; "open entry" races along the lines of the Pro-Am events in the Iron Curtain days may even lead to more interesting fields, if not higher level fields. No matter how much money UCI throws at a substitute Tour de France, it will not be the Tour de France, just a parody, a facsimile thereof, just like the US500 at Michigan was a complete failure at replacing the Indy 500, or the Friendship Games for the Soviet bloc nations when they boycotted the LA Olympics.
Like it or not, ASO has the control in this game, and given some of the ludicrous things the UCI has been trying to table since long before Brian Cookson's Ecclestonesque self-interest group took over the helm, that isn't actually a bad thing. Under Pat's watch we had the Tour of Beijing and the mooted World Tour Tour of Russia, the desperate attempts to make California ProTour, the enforced internationalization that led to farces like Euskaltel at Roubaix every year or year 1 Orica in the Giro where they couldn't muster enough finishers to qualify for the Teams Classification, the happy handouts of ProTour licences to anybody with money regardless of what they actually brought to the table at the expense of long-term investment and stability. Under Cookson we have had the no-overlapping, no-race-over-six-days rule, the 22-riders-per-team rule, the move towards ticketed, popcorn-selling circuit racing and the attempt at developing a calendar with a top tier tour of just about every pan-flat oil rich state in the Middle East and the relegation of the likes of Catalunya and Romandie to nothing races.
ASO are reactionary, conservative and, because their current position is one of strength, extremely resistant to change. But as long as the changes that are being tabled are counterproductive at best and short-sighted money grabs at the expense of the entire history, culture and romance of the sport at worst, that's actually the better position.