The UK train system is a dire, expensive mess. Attempting to avoid getting directly political here, but I strongly believe it’s one of the lowest hanging fruit a political party could act on to curry favour with the electorate. Would be amazing to see this productised à la the way split ticketing works.
As a North American who travels in the UK multiple times per year, I really need you to elaborate. My experience has been nothing less than amazing, in comparison to the complete lack of rail options at home.
It also varies a lot in different places. Costs vary with types of tickets, who you are, and whether you have various discounts.
Local train services are very weak where I live (Cheshire) so while I can get to major cities quite easily its difficult to travel between towns in the county on trains (or buses).