They can always get the scroll b4 head out... and Comrade's Succour is not some ritual the party needs to cast all the time...
And 2600 gp is abt casting the ritual 16 times, assume you take 2 extended rests per lvl, that means breakeven at lvl 11... well my bad, not mid paragon, early paragon...
yeah, even without a ritual caster, by the time the investment starts to pay off, the party is probably in mid paragon, and probably does not care about the extra 160gp per day expenditure..
Guess the DM just need to rule that the alchemical items created in such way cannot be sold... so essentially, you will just have unlimited alchemical items, which isnt really a big deal.