I do think the statutory PF is too low, which is I think what leads to Penalty Fakes.
I think there should be a trial at one TOC, whereby that TOC agrees with the DfT that it won't prosecute any Byelaw cases (only serious stuff, e.g. forgeries, that justify the use of RoRA) and will instead use statutory PFs, and in return the PF is increased to £80, discounted to £40 if paid promptly or on the spot for a first offence in a 12 month period only, increased to £120 if paid late. The Anytime Single fare for the journey made would be payable in addition. This would be non-fault, i.e. it would apply whether the evasion was intentional or a mistake. RoRA would only be used for serious cases of fraud such as forgeries, never for simple ticketless travel, nor forgotten Railcards etc, and definitely not for slightly smudged Carnets.
That would probably make quite a difference.
As for LM, it near enough gave up on revenue protection so is not really a good example. There is still basically no revenue protection going on other than at the Euston and Watford barriers (and sometimes, but increasingly rarely, the MKC barriers) on the south WCML services, except a small number of guards who do do tickets, but if you don't have one you just get sold the same as you'd have got at the ticket office with all discounts.