The key driver is demand.
Distributors are not a magic bullet, they will not push or promote your product or otherwise get you to an audience that you could not previously get to.
In many cases the only value of a distributor is so that you do not need to extend credit to your dealers and handle pick/pack/ship operations. If you're looking to get picked up by a distributor as a sales strategy, you need to seriously evaluate that strategy.
Most distributors are happy to pick up a product that has clear demand. If you have more demand than ability to fulfill, distribution is a good option for you.
Most distributors are not happy to pick up a product that is low demand, has a complex sales cycle, or takes a long time to explain or sell over the phone. They are all about high volume/low margin (generally speaking).
Keep in mind too that most distributors will want or expect you to also do some marketing with them. You can easily spend $5,000-$30,000+ annually with each distributor to get featured in email blasts, print catalogs, lunch-n-learns, or other similar programs. I honestly think some of them are marketing firms with a warehouse attached. You need to evaluate the incremental business you will get, versus the cost of doing business.
I'm not saying distributors are bad or useless, they can be very helpful in scaling your sales when you understand their true purpose and potential. But, simply getting Anixter to carry your product won't result in any incremental sales simply by virtue of being in their system.