I was shooting portraits a few weeks ago at a park and had my big white 70-200 f/2.8 IS. We walked up on a wedding party that was shooting photos and their photog's gear didn't equal mine. I kind of giggled in a schoolyard singsong way "my lens is better than hiiis lens" to the client--just being silly. The client's face lit up. I saw members of the wedding party looking at me shooting pics of 2 kids with the big bazooka and they just kept staring.
When you get into terms like "quality" in an artistic business such as this, much of it comes from the perception of the client. If my client's perception of me was heightened in that moment, that's great. It increases confidence in how the final pics will turn out.
When you actually shoot for money, lenses and cameras should be the cost of doing business. It's part of the perception of you as a professional. If you've got a silver Rebel with the kit lens, you're not seen that way. I've seen photographers from huge studios taking photos with cameras and lenses that I would simply dismiss. It's pretty obvious to me that the studios were keeping the costs down because they employed so many photographers and probably had huge investments in the QUANTITY of gear they had to buy, so the QUALITY suffered. The sticking point there is that these outfits already had the contracts, so they weren't really out to impress anyone with their photos. They were just trying to provide adequate quality (which, after seeing the photos, I personally question).
If you pick up your date in a beat up '77 Chevy Van with doors rusting off, you will be able to take her to dinner and a movie just as well as picking her up in a limo. It's not really about what's possible, or "good enough". It's about perception and what will lead to continued success.