They are building too many steam engines. It's a bubble that's going to pop and leave investors empty handed. There are only so many mines to pump water out of, mills to turn, textile machines to crank. And those industries have jumped on a bandwagon that they don't understand, and most will soon mostly revert to good old English laborers. His Majesty's subjects are starting to see the terrible environmental effects of burning so much more coal. As a prudent investor I now recommend a Sell for the stocks of the Boulton & Watt company.
This did pretty much happen with railways during the industrial revolution. Huge amount of money was invested into railway build-outs and most investors lost their money even though the result was useful in the long run (though only a subset of what was built).
The bottleneck was the phone line running into individual houses. ie The "last mile" was a bottleneck. Dial-up. If you're old enough you will remember people connected to the internet via Dial-up, that is, their phone line. It was a bottleneck. It's data capacity was nowhere near what the fiber was.
Those popped all over Europe during the entire century, with the last one popping at the 1890s. For some reason, people focus only on this large one on the UK.
Sources for how 19th Century imperialism had a lot of support from extend-and-pretend infrastructure bubbles are harder to search.
