In Europe while the airlines allow multstop flights even on low fares, the reason why not many people fly multistop mileage runs, is that almost all European network carriers charge high per segment surcharges on top of the high departure and landing fees. So for example, a 99 EURO HAM-PAR good deal flight (advertised incl. all costs) on LH would be 99 EUR direct (with the fare being 10 EURO basic plus 39 EUR tax plus 50 EUR fuel and security surcharges for 2 segments), connecting throu FRA and MUC each way would add 4 segments, so the fare would end uo being still 10 EUR base plus 117 EUR tax plus 150 surcharge, total 277 EUR.

(the amount of taxes and surcharges isnt exactly like that, but this shows the system how mileage runs by multistop flights are not very popular over here)