I dont know about the bags ive never used them.You say that it is a lot of work to wipe strings off + then apply wax.Believe me i do this after i am done playing or before i play the next time+it only takes a couple of minutes at the most.
I would also say that it can make more than a little difference, i have done nothing with the gut strings+ then i have done the maintenance i desribed + they will last at least 30% longer when taken care of.When you figure $30+up for the top guts that little bit of time is worth it.
As far as the varnish they sell for strings, that will also help but again they wont start to fray near as quick if you use my method.The waxing + stringsaver before the string starts to fray will do much more than the string varnish.Once you have to start using glue or varnish on the strings they are on the way out,but it will help you make them last a little longer.
I have had gut strings last as long as 8 weeks+ that is playing everyday.I use western grip with a lot of topspin so i am hard on strings, many syn. strings i will break within a week or so.
What i do is put a new set of gut in+that racquet is for matches only, which i play at least 3 matches a week.The other racquet with the older gut job is my practice racquet.After a about a month or so i will sometimes break the strings, but usually they are getting to loose for my likeing, most of the time i cut them out because i want the tighter tension feel.
Then i restring the stick i was using for practice+ the other one becomes the practice racquet.This is a good method for getting the most out of your gut.Even the practice racquet with the strings that have 6 weeks of time on them rarely break+when i am not playing matches i am out practicing+ banging a lot of serves.
By the way i do use pacific toughgut+ it is by far the longest lasting gut you can buy.I have even been lucky+ found some of there uncoated gut + i would still get at least a month out of it.
For the average player who plays a couple of times a week, unless you are a big string breaker you could get 3 months out of a set of gut with the proper care!