I agree, I have always thought that this would be certainly the best way of serving the stations between Liverpool & Wigan. The artificial gap between services at Kirkby is just plain daft, as is Ormskirk.
What is needed is joined up thinking and a proper plan for all the rail services in the North of England. But that would require some one in Government to actually have the nerve to think longer term than the next election. Don't hold your breath.
I don't disagree, but the problem, as often, is money. On the Preston line, Merseytravel is not likely to want to spend money to improve services outside its area; Rufford & Croston are too small to encourage West Lancashire Council to provide most of the costs of electrification. Moreover, with the possible prospect of 2 trains per hour between Lime St. & Preston, one maybe taking only about 45 - 50 minutes, this would likely be faster than an all stations service via Ormskirk. 3rd rail eventually reaching Burscough is possibly the best that we can expect.
On the Kirkby / Wigan line, neither Rainford nor Upholland stations are close to the nearest centres of population; Orrell & Pemberton have good bus services to Wigan. Therefore, in the present financial climate, I don't see Greater Manchester wanting to contribute much towards any scheme that improves services to / from Liverpool.