I am partially in agreement with what is being said here.
We need to be clearer that Agile / Scrum is not a project management methodology. It is a software development methodology. It does not offer a model for planning, period.
Also it brings some new concepts that do affect how work should be approached, now in terms of “products” rather than “projects”. But it actually creates an issue that it does not resolve around planning.
Agile (and Lean) only focus on the flow of the work. Not on planning the end dates.
Enterprises need planning. Not everything can be just left to a flow. At least not until major-mega-big transformations have occurred. By creating a problem without a solution, a lot of the frustrations are emerging as a result in the Agile journeys of most Enterprises.
Agilists argue that until the Enterprise has reached this major-mega-big transformation, it is not going to work well, making the case for more transformation, but also leaving a trail of chaos along the way. This is generally winding Exec Management up and detrimental rather than helpful to Agile transformation.
Another approach consists in doing this small enough at first to not need big solution and move quickly from this. This again struggles to gain traction in big enterprises.
There is a need to establish planning substitute outside of the Agile flow and in a way that is compatible with an Agile operating model / experimentation cycles. Even if the end-game is to have short cycles as the norm and the organisation aligned around this, there needs to be an intermediary approach to planning.
I am actually thinking of this and quite a bit has already been written on the subject. Something like speculative planning rather than predictive planning. Estimation of the work is banned, it should be based on true progress, and mapping the future volume of work (with the various levels of granularity of its definition to past work). eg. #of Features per flow / #of stories per feature / avg story size, etc. The key thing is that never people estimate the backlog, this should be based on observation and true pace of work. You may even model resolving waste, improving velocity, etc. and eventually establish ETA of the desired key features. The understanding of such models is that it is only speculative and non-committed by the team as the scope is actually unknown. In such model some traditional artefacts of planning could still happen under the understanding that all is only speculative.
Driving change is very much about understanding the reasons for resistance to change, derisking the situation, educating, creating a zone of comfort that enables progress to a better state. I believe that establishing an approach to planning compatible with Agile is necessary to help enterprises transforming.