From a commercial point of view, that's an easy decision. One ticket sold for £100 is better than three at £25.
If, as a society, we prefer to sell more tickets for less money, that's a political decision and it's up to government to fund any shortfall. If the rail operator is a private company, we might also compensate them for lost profits depending on the circumstances.
I'm not against any of this, but you need to express your preferences at the ballot box.
The electorate of Scotland have been doing that since 1979 with the following voting patterns and results, which are below:
1979 - Mainly Labour, got Conservatives
1983 - Mainly Labour, got Conservatives
1987 - Mainly Labour, got Conservatives
1992 - Mainly Labour, got Conservatives (only just, due to a late swing in the day to the Conservatives)
1997 - Mainly Labour, got New Labour (which were not new, and were most certainly not Labour)
2001 - Mainly Labour, got New Labour (which were not new, and were most certainly not Labour)
2005 - Mainly Labour, got New Labour (which were not new, and were most certainly not Labour)
2010 - Mainly Labour (with the only constituency changing hands was mine of Glasgow North East from Speaker to Labour), got Conservative-Lib Dem coalition
2015 - Overwhelmingly SNP (with 56 out of the 59 constituencies, with the remaining 3 being 1 each to Labour, Conservative, and Lib Dem), got Conservatives (only just, due to errors in the polling methods)
2017 - Mainly SNP (reduced to 41 constituencies), got Conservatives with some support from DUP
No matter what the voting pattern of Scotland is at General Elections, since 1979, Scotland has not had the government it has voted for. Although I do understand the reasons how Scottish nationalism has become fashionable nowadays, I do not support the SNP's version of independence. I would like to see the whole of Great Britain (assuming Northern Ireland is returned back to the Irish) having progressive federalism, but this topic would be better in the General Discussion section rather than here.
Mods: I was simply picking up on the last sentence regarding expressing preferences at the ballot box, which the result may not reflect the voting patterns long term across any given part of the UK. I will add a reply about fares soon.