Out of my 16 solo wins I am sure that at least 15 were won with zero gold use. I tend to only use gold against other players that use gold to inflict more damage/cause more losses. Pretty sure also I have not payed for gold since I am out of my rookie fase.

In the beginning more than now a days, since I now know the game quite well building stuff, training units and doing research goes somewhat automatically for me now. That means I can put all my focus into strategy. It can be harder if I run into a good player or multiple good players, or a group of average players that work together really well.

Yes, but you'd be surprised where you can get if you find ways to fix your mistakes.

Depends on the map, Larger maps can take between 1 and two months and smaller maps usually less then a month.

If I commit to winning a map solo I don't join any coalitions and just fight everyone or let everyone fight each other.

My profile page says I have 40 solo victories; and like Edepedable, I only spend gold against obvious heavy golders to make them spend a bit more, so most of those victories are without gold spent. I usually play the 100p map, cause that's the best chance to find a decent opponent somewhere. Games usually last 3-4 weeks for a solo victory, barring speed games of course. I also have 19 coalition victories; I tend to join them when they don't form at day #1 and seem to have some decent players in them, and when I'm in a lazy mood and don't feel like doing all the work myself. In the end, they last about the same time.

I don't really care how much gold a victory pays; I still have almost 2M gold from the time I was a staff member, and hardly ever use it, see above.

Like everyone else, I have stacked up a bunch of wins without gold. I've been fortunate enough not to encounter gold users much but often players who rely on gold to win aren't very good strategists and this often is their downfall.