The NortonLifeLock spin-off wasn't an instant decision that's been taken over a cup of coffee - Symantec saw it coming in 2014. Throughout the years, Symantec has maintained a large portfolio of business products, adding more and more products on monthly basis. Symantec's approach wasn't consumer-friendly. It was rather product and profit-oriented. In Q2 2015 Symantec had a conference in a luxurious hotel in Central London (near the St. Paul's Cathedral), where the future of the company was decided - the Veritas division had to go. Veritas was generating unsatisfactory cash float not only for Symantec - the company had been acquired countless number of times and then resold, as its products don't really meet the consumer or IT administrator needs. One veritas product was Norton Ghost or its business version Symantec Backup Exec. These solutions, without stepping in to too much details, did not evolve one bit throughout the years. When "cloud" as a term and "cloud" backup became a thing, Veritas portfolio quickly became obsolete, on top of being difficult to manage.
After the Veritas demerging, the company became increasingly unstable, it's shares were going constantly down, the management had changed, CEOs were coming and going (Symantec worked without a CEO for 6 months and in 10 years changed 6 CEOs) and it was clear that, either the company will change its approach, or it will become a thing of the past.
Symantec, that was once winning awards for being one of the most ethical companies, 7th to be precise, after Adobe, was caught red-handed "n" number of times. Source code leaks, financial fraud, scareware tactics, bogus website certificates...all that affected the ability for the Norton division to research and innovate, as well as investor and shareholders relations with the company. The Norton division was kinda ripped of by Symantec, having to sponsor its increasingly dying business portfolio on one side and coping with its parent company's "bad reputation" on the other. Endpoint Protection was another line of products that was evolving at unsatisfactory pace in a highly-competitive field. It was stuck on V.11 and 12 for 2-3 years, and major enhancements such as SONAR and Insight were implemented 2-3 years after being available in Norton products.
When the Bluecoat CEO Greg Clark was appointed after the company merger (that was the period when Symantec was working without a CEO), he did mention couple of times that the consumer division has to be spun off and the business portfolio has to sold out to someone, better prepared to run it. There were indications under his management that a spin-off is coming. In late 2018 the Norton by Symantec logo was replaced with Norton LifeLock.
When Greg Clark stepped out of Symantec, just as many CEOs previously did in May 2019 (most probably under the pressure of the board of directors, as they did not quite like his vision), Richard Hill was appointed. At that time many people that I know, left Symantec - a long time community and support division manager, who I follow on twitter very closely and I've met here in London, shocked me with the news he was leaving the company - he was on Symantec's forums as head of Enhanced Testing so long as I remember the company, or having a PC. And he did mention it is not only him. Symantec's management wasn't great.
The final push towards the spin off was Broadcomm's interest in Symantec. That was the perfect opportunity for Symantec to let the consumer division finally breathe - and that's what they did. Richard Hill did not allow Broadcomm to absorb the consumer division, although Norton is the main appetizer for the acquisition. The NortonLifeLock will be far better off, not being under the Symantec umbrella anymore, but rather financing only the STAR team and managing its cash float the way it has to be managed. That's kinda like Norton paying Symantec exactly for what they need, instead of Symantec (now Broadcomm) taking all the cash and then feeding Norton with some breadcrumbs. It is unclear to me however, why Broadcomm sold certain parts of Symantec to Accenture. IMHO, Broadcomm will quickly get rid of Symantec in an Intel-McAfee-similar way. The entire scenario so far is just too much Intel. It is also unclear why NortonLifeLock had to go public. It would've been a lot better as a llc.
While neither I, nor anyone else can predict what will happen to Norton, Symantec's LifeLock buyout was an extremely smart move from their side, as this is the future of security. The upcoming months while the separate entity re-settles on the market will be critical. In the future, market analysts are expecting the company to stabilise.