The first example that came to my mind was the building of canals.

Many canals didn't get finished (Leominster eg) or lost money when they were completed, dividends were modest. Then when the railways came they lost money to the point they were vulnerable to the railway companies who wanted their cuttings and near zero inclines. Pick yer timescales as to cost/profit - think restoration!
My own Stroudwater currently needs £18 million to connect the restored section to the system. The 6 miles already done cost over £10 million. The benefit is: I can walk to Stroud unparticulated along a pleasant verdant corridor. The payback is ephemeral, but I favour the project, so that is justified. Oh Yes It Is!

Change costs money. Payback period is never instant. And something as complex as a country replete with H&S, Trading Standards, and self-serving politicians etc is not what I would class as simple. Hidden costs are in there. And consequences like a nationalised bank opening a new trading house in Europe to be able to compete are but the tip of the proverbial.

In the long run you are predicting the future from historical experience. It is a hope (aka belief system, aka religion) that 65 million comfortable peeps can compete with 2000 million low paid. Who can buy us out!
In the short run the pound is weaker and your food is costing more, and there is more to come!
Global warming will confuse the general picture to the point that the yessers will have a getout. FWIW Global warming is a change that will cost! Like more rainfall. Any current evidence/consequence/cost there?