In the news article I read this morning the CPS are still considering whether or not to bring charges so he hasn't definitely escaped prosecution yet although I think voluntarily surrendering his licence will help with that because he wont be a future risk to anyone.
In the UK you do have to retake your test when you reach the age of 70 and then every 3 years after that, you are also required at any age to report any conditions or factors that impair your ability to drive safely so the vast majority of the UK pensioners are passing safety checks and legally meeting conditions to retain their licence.
I do think there is an exception where Prince Philip is concerned, royalty are often not obligated in the same way and certain laws are not always applied to them as they would be non royalty but he has at least admitted he isn't fit to drive by giving the licence up and there isn't much more he can do, the apology was a little flimsy and delayed in the opinions of many but in an ongoing investigation or even a potential insurance claim drivers are actually advised not to apologise until the case has been settled.
My husband was hit whilst stationary a few years ago, the other vehicle was travelling at 60mph, thankfully no serious injuries occured but there was no apology to my husband, our insurance company just took over, claimed his losses and the insurer of the other driver paid that and also had to pay for the cost of physiotherapy for the whiplash my husband sustained, of course an apology from the idiot who hit him would have been a considerate thing to do but before settlement it is considered an admission of liability and even after it is not legally required.
Philip will no longer be driving, he did apologise even if it felt 'forced', if she has losses insurance will recoup them, she is not hurt and he isn't in the clear as far as the investigation is concerned, I fail to see the outrage at this outcome.