They can't. Labour won't either, and for the exact same reason.
Both are wedded to the idea that growth is natural. It isn't, it is driven by investment or asset inflation.
Neither party will invest, in fact both are talking about reducing government spend.
This was OK for blair, who simply inflated assets to compensate (house prices tripped between 1997 and 2010). The asset increases and cheap borrowing meant growth was fuelled by value extraction - people borrowed against the increase in value of their homes, and then spent it in the economy.
But since 2008 that doesn't work. People can't afford to borrow any more, and government are not investing.
The world changed at the crash, and our politicians, with the exception of corbyn for a while, have spent the last 12 years trying to hammer the square peg of what they did before into a round hole to achieve the same results.
It cannot work. Ever.
And whether you agree with corbyn or not is irrelevant. He at least understood that 2008 meant we had to change direction. Not one of the 'adults in the room' before or since had the sense to see it.
As well of course as the self inflicted problem called Brexit.
I mean how can you reasonably expect to increase trade when you tell your biggest trading partner that you are better off without them.