Indeed, it's a complex topic. I was reading an article just the other day on nuclear targeting strategy(1); the thought that goes into this and how it interacts with the greater warfighting strategy, or arms control agreements, is daunting.
Suffice to say, the land-based fleet still has a role to play. Other powers still have or are expanding theirs(2). Arms control talks need to get back on track. But until then, a balance needs to be kept.
As an aside, I read the book "Inventing Accuracy" a while back; a really interesting look at the technology that goes into missile guidance and how it drove policy and strategy. Great read(3)
A fundamental reason behind the new expansion of the nuclear arms race is the spread of anti-ballistic technology (shooting down incoming warheads and missiles). The article doesn't mention it at all oddly enough but I think that's the primary driver behind things like hypersonic missile development, etc.
> "Twenty years ago today, then-president George W. Bush announced that the United States would withdraw from the Anti-Ballistic Missile (ABM) Treaty. This cornerstone of the Cold War arms control regime, signed in 1972, sought to cap the arms race by limiting homeland missile defenses, thus reducing pressures on the superpowers to build more nuclear weapons."
https://carnegieendowment.org/2021/12/13/u.s.-exit-from-anti...
> "Twenty years ago today, then-president George W. Bush announced that the United States would withdraw from the Anti-Ballistic Missile (ABM) Treaty. This cornerstone of the Cold War arms control regime, signed in 1972, sought to cap the arms race by limiting homeland missile defenses, thus reducing pressures on the superpowers to build more nuclear weapons."