Fixing your cable problems forever.

One major financial benefit to making your own speakers is having direct control over the sound balance.

It is much more effective to change a tweeter or midrange cap, or adjust the level or balance in the crossover than to play the amp/cable/power cord swap game.

Over the years I have built my own IC. Used a spool of wire to make speaker cables. Made power cords with premanufactured parts.(I would think making one's own IEC or AC plug would be daunting.)  
Currently all my IC are major manufactured, So is my Speaker cable.But I do have a long dual homemade extension set I have used foe many years.And currently two power cords I built, of many bought.The two home made cost $300 each, mainly due to using Furutech 28 series Rhodium plugs, with $8 ft wire. Sadly they are no better than my Pangea store bought power cords.          
The most cost effective wire I used was home made speaker cables. Really almost as good as the store bought ones for a fraction of the price.

+1 erik_squires- with diy you can really tweak to get the best response with your equipment/room.  With my diy speakers that meant upgrading the caps from Clarity Cap PX to Mundorf Supremes.  They remain a work in progress; with a commercial product I’d certainly be more hesitant to dig into the guts of a crossover.