I am a senior portfolio manager at a large professional services (consulting) firm, and have about 40 people reporting to me. I interface with high-level clients and manage multi-million dollar contracts.
In my 20+ year career what I have absolutely noticed is that how you present yourself matters. But I am also amazed at how many people think this means you have to wear lipstick if you are female! I think it's important to both be comfortable in your own skin, and to project confidence, regardless of your career or field. If you are confident and skilled at engaging others - whether you are a landscape gardener or a management consultant - you are going to be successful, with or without mascara.
That said, in some industries (mine included), dress code ABSOLUTELY matters. I have sent junior staff home on days when we had clients coming to the office and said staff were not professionally dressed. In our case, and depending on the client, this does mean wearing something you have to send to the dry cleaners (usually a suit). But mostly what it means (and yes, I am clear about this with staff) is that you come to work polished and pulled together - and exuding confidence. I point out that we are highly paid consultants, and our image needs to reflect that. The way we are dressed reflects the respect we have for our clients, and should match or exceed the clients' own dress code. But all that said, to me "dress code" does not imply makeup. I don't wear it myself (unless you count sunscreen on my face, LOL), nor do I expect it of my staff. (And I don't expect the men on my team to be clean-shaven, but if they have facial hair, I do expect it to be neat and not scraggly.) I have noticed, however, that those from the south or midwest are far more likely to do the makeup thing - so perhaps is is geographically cultural.
I will also add that one of the most successful young women on my team has a visible tattoo and a couple of piercings. When she was first hired I pulled her aside and said that I didn't personally care about her body art because I knew how smart she was, but I also said that she was going to have to be careful with how she presented herself to colleagues and clients, because people were going to make assumptions about her based on how she looked. She rolled her eyes and said, "You're going to tell me I have to wear makeup to work, aren't you?!" I was stunned, because it honestly never occurred to me to tell someone to get on the mascara train! After I finished laughing, i told her I would never request any such thing - but that she was going to have to make darn sure her smile was brighter, her cuticles were cleaner, and her pants were creased sharper than everyone else's at the table - because that's the kind of industry this is. I know she thought I was nuts, but many months later she mentioned to me that she finally understood what I was talking about! She still doesn't wear makeup, though.