Fusion is basic science research. In a few decades it may become engineering.
Making solar and storage cheaper is already engineering.
I do expect fusion to out-compete solar and storage eventually, but probably not in the next 50 years unless one of the fringe groups does something amazing.
The basic science research has already been conducted.
What is being done now could be viewed as engineering, as the goal is to scale the process to a large size, such that the system may deliver a 10x return on the power going into it.
When we have an experimental reactor that produces electricity reliably, then the engineering can start. Up till that point it is still science research. There is engineering involved, but the engineering is being used to construct an experiment.
edit - and ITER has not been inspiring confidence. They seem to be massively bogged down at the moment, though we shall see if anything picks up now that they have swapped management and are trying to rebuild the organization.
I'd argue that making solar and storage cheaper is not engineering. Currently, their efficiency and capacity do not warrant widespread use. More research should be done before money is wasted deploying half-baked technology.
You can try to engineer cost savings and efficiency out of the current solutions, but using all that brain power on something that might yield single digit percent gains is a massive waste of talent IMO.
The minds that are working on those problems would be much better utilized working on solar and storage research as well as more long term solutions like nuclear fusion (NIF, ITEF).
Without subsidies, civilian nuclear would not exist and we'd have a lot less oil and gas supplies. Exploration subsidies for oil and gas have doubled in the last five years in the US.
edit - energy production is always subsidised in wealthy countries, as energy security is key to national security, so it would be stupid not to.
Making solar and storage cheaper is already engineering.
I do expect fusion to out-compete solar and storage eventually, but probably not in the next 50 years unless one of the fringe groups does something amazing.