Stationary? The way I see it modern combat is about cutting off supplies and surrounding enemies war has always been like that. The tactics used in combat differs from terain and or the situation. If you got a large open field like the ones I saw in Ukraine you will have battles like in Kursk because I just saw footage of Ukrainian and Russian backed tanks engaging each other in an open field. War has changed very little except for technology, the Germans in WW II was responsible for mixing Blitzkrieg modern combat with WWI trench warfare or as you call it "sit and wait". Modern war is never urban only... As things unfold in Syria I guarantee you... You will see the real face of warfare... Land, Sea, Air, and Space.
You saw ten thousand tanks roughly engaging each other?
.-. I doubt it.
No, the era of large grand battles has ended, you have skirmishes, bombings, insurrection, terrorist reaction, a few invasions here or there but the era of war you seem to describe of when you think of 'battle' has been dead since Vietnam. There is rarely a war between two industrialized nations with access to the high military spectrum. That said I do think it was sort of cute that you said: "You will see the true face of warfare" You made me smile with that one, I will admit. I like smiling, I rarely do it but I enjoy it.
You want to know what my experience with war is? Iraq-Baghdad, it was urban warfare supported by armor and aircraft. It was engagements with regular army units in entrenched positions, their best units in entrenched positions, and their armor and artillery in entrenched positions. Angola was in align with what you said but that wasn't even a war, it was aid protection. You want to think that starving militia charging aid drops you were assigned to protect and ensure distribution of as battle? I didn't personally, but I guess you could call it that. No the era of war being described as anything but anti terrorist reaction is over, unless if another regional skirmish breaks out like in Ukraine but even there it's just a giant fighting a gnat. Its being done this way because of international attention, nothing more.
No, there is no reason to fight in fields or the ocean anymore, there is no invasion of a enemy power to warrant it. There is no real antagonist in this chapter of human history save those who do not have a nation, its hard to invade terrorists. They are simply people with a ideology, Iraq was a nation, it was a place on a map you can send forces to. But that's the exception to the rule of modernity.
You want to think that era of massive battles will come back? You are welcome to, I don't see it. Not in the current political climate, not at present.