I've mostly only ever worked in Windows environments with the odd linux machine here and there, but mostly Windows, I've worked in both I.T. and product-oriented shops. I've mostly favored spaces. I've never been questioned it or asked to do differently. Generally speaking, those that care about the money, don't give a fuck about whether I use tabs or spaces. I've worked in tight-ass shops that have nickeled and dimed for every cent savings and I've worked for shops flush with cash to pay developers to do it right.
In my actual experience, I've never seen any relation to tabs vs. spaces with regards to being paid more. Nobody that has ever paid me for what I do has cared about which I use, nor have they questioned it.
One thing I have noticed in programmers are an asset vs. programmers are a liability is that companies who understand that automation is going to extend their profitability by more of a margin than it costs them will pay you what you're worth. Those that view programming as a sunk cost, that just makes their lives easier or cuts costs will pay you what they can get away with.
Don't work for a company that views you as a cost centre. Work for a company that views you as a profit centre. The work will be more meaningful. You will be more fulfilled. You will most likely be less stressed and you will most certainly be appreciated and respected more.
Case in point - I use the default Visual Studio settings which are spaces, BUT they weren't always. I remember as recently as 2008 tabs were the default.
You got it backwards. In companies that sell code, code is an asset. In companies that sell services code is a necessary evil.
If you're a software developer and you're part of the "IT" department, then you're a liability. Your code is a necessary evil.
If you're not part of the "IT" department, then you're working in a product-oriented environment where the company is selling your code (either as a good or as a service) or otherwise making money from the code. In that case, your code is an asset.
I'd also like to see an analysis of space-vs-tabs as it relates to operating systems. Again, from anecdotal experience, it seems spaces are more common for folks with *nix background who tend to work in product-oriented companies (i.e. where code is an asset) and tabs are more common with windows folks, who tend to work on IT (i.e. where code is liability)