This problem is more complicated, than it looks like.
In the past the most popular maps costs about 40 000 - 50 000€/month. Then there were a lot of complaints, that maps are too expensive. All prices of concessions were lowered probably by 50%( maybe less, maybe more). The most used maps are now around 30 000€, which is really not high. We got higher ranks, players has higher revenues than before. So where is the problem?
There is problem that there are still more and more companies, which want to have the best maps, but the problem is that there aren't enough players. This is dangerous spiral for the future, and will lead into another problems. If the map concessions will be again lowered, there will be again more companies and less players.
But let's go back: There are multiple factors, how the price of concession is calculated. To be honest, probably all maps normally costs maximally about 5 000 - 15 000€/month (this is standard price without global calculation (number of owners)), but the price is overpriced due to other factors - the more companies have this map bought, the higher will be price of the concession. This is caused by multiplayer "coefficient".
So if map concessions will be lowered again due to some mod splitting, it will be in one year same as before. More companies buy this map, the price will again will be higher.
The reality is that we are talking about a few thousand € per popular map, if linien packs gets priced as "something more". Linien packs are only on a few maps, we are mostly talking about Ruhrgebiet, A&L, Ahlheim V4, Krefrath and some other small maps. Do you really want to spare just maybe 5000-10 000€/month on a few maps, which will cost due to mod splitting more again in future?
If you think you are paying more than 10 000€ per map just for the linien packs, you are probably wrong. The price is not that higher due to more lines.
PS: If you have to low prices of the maps, you can create local company, where the prices of concessions aren't affected by multiplayer coeffiecient - this is why the maps are expensive in MP. All concessions costs are there just a few thousands (as I said maximally 15 000€ per map, but mostly all around 8-10 000€).