If kits were a lot more expensive, but a lot more powerful once bought (because they are usable in every match) wouldnt that'widen rather than narrow the advantage of a premium user who could afford the high cost easier?'
Rethink your approach to kits depending on your state of play;
when farming for a new build (I mean saving up, as money is required to buy a mech) its not unreasonable to give up a game if he pops a couple of kits - but if you quit, you get nothing right? being loser you get a reward - not sure as I have never quit a game (well I did once, but I forgot if I got a reward). So its better to pack up your droid and drop your shield and die than quit, and its better to fight than do that

I enjoy trying to beat him when he used a kit without using one myself
When not saving for a specific item or set, a kit is easily paid back by a couple of wins without kits and hopefully a win in the match you used the kit.
Simply put; kits are not game-breakingly expensive.