Even if the breach is not true, why take so long to deny it ?
They have to conduct a proper internal investigation before they can confirm or deny something. Without evidence of a breach, they cannot confirm a breach. And it would be wrong to deny a breach if they haven't yet conducted an investigation to determine that there's no indicators they had been breached.
These investigations can take days, weeks or longer. It depends on what the alleged breach is and how skillful the attackers were. There have been breaches that have been discovered by a company years after by running into things that were unexpected or anonymous tips.
I respect that you do not like Norton anymore, that's fine. I had a period where I really didn't like them. It was pretty much the entirety of the old days when they were causing more harm than good, had ridiculous amounts of FP detection's and were much buggier. I personally do not like the Norton product line-up that much but I am a fan of the Symantec Endpoint Protection/Cloud products - which you can trial if they will let you and take a look at, it's roughly the same price as a cup of coffee in some places per month for one device.
I should probably drop here that even Microsoft of all people suffered from a major breach awhile ago by an ex-employee of Malwarebytes who managed to hack into their servers and access the source code and other secrets of pretty much anything he wanted to access - it went undiscovered for several months, at-least. The ex-employee shared access with other hackers on chats as well. In the end, the ex-employee was caught and arrested and put on bail - whilst he was on bail, he hacked into Nintendo's servers. Thousands of searches were committed between the ex-Malwarebytes employee and the fellow hackers he was sharing access with to the Microsoft servers.
The ex-employee was finally caught by Microsoft when he uploaded malware to their servers and it was caught. This brought attention to Microsoft that someone has been misbehaving and resulted in him being caught as well as the fellow hackers he was sharing access with.
Reference:
Security researcher pleads guilty to hacking into Microsoft and Nintendo
Microsoft have been breached numerous other times. Wasn't there a fiasco about Outlook breach recently? Either way, two men were arrested a just over a year ago if I remember correctly for stealing from Microsoft servers, I believe it was the Windows 10 source code.
Windows NT 4 kernel source code was leaked in the early 2000s and today it is hosted on GitHub. Windows Research Kernel which is given access to Universities to help students learn about OS development and corporations for debugging purposes/general research was leaked by someone many years ago and is also hosted on GitHub now. Microsoft stopped bothering to fight the leaks because they know they cannot do anything about it anymore, it spread too much over the last decade.
There are breaches all around you and I suspect you still use Microsoft Windows even after all of Microsoft's breaches. I'm not trying to push the opinion that you should "like Norton" but just provide some insight to the fact that Norton aren't the only ones who have been hit with a breach and more companies you rely on have been affected twice as bad as Norton.