How did Britain go from being capable of building large-scale infrastructure projects to being so incapable? And how do we fix it?

HS2 is an obvious example, Heathrow expansion another and even new-town building. There seems to be endless bureaucracy, the initial cost of projects always balloon and every politician across all parties seem to acknowledge this issue but fails to address it.

We aren't a particularly large country, surely high speed connections between our major cities in the modern age for the world's 5th biggest economy should not be considered a pipe dream. Wales doesn't even have a north-south rail-line entirely within Wales.

Connecting new housing developments with public transport and building new infrastructure to accommodate them is something every politician talks about being a necessity, but private companies are still building large housing estates with none of that. A lot of new housing developments also aren't the best quality of homes, built as cheaply as possible for the greatest profit margin with limited greenery and no use of local skills to add character to properties.

Water is another major issue, why have we not built a new reservoir in over 30 years? Why is the water grid so under developed? How is Poland exceeding us in reservoir construction?

Everything takes so long, housing takes so long to build, railways, reservoirs, airport expansions. There's no shortage of brownfield sites.