Powerful machines at home and readily available graphics software that doesn't run into thousands of pounds does really help the little guy, but here's my opinion on that one.
I have worked many places, large and small, as well as working remotely for several individuals prior to that.
A current major TV show has hundreds of VFX-heavy shots in one episode alone, more than most feature films a decade ago. Although things are indeed quicker now, both in terms of hardware and software tools available, one or two individuals would struggle to deliver this to a high quality on time, though they'd be nicely underbudget potentially, leading me neatly onto... people!
The benefit of a small team rather than a huge one is that communication has to be clear and fast or things get delayed very quickly. One thing imo that I've seen in many places, especially the larger ones, is that if anybody in production or HR takes their eye off what their teams are actually working on and how long for, costs escalate super fast. Equally though, a new director wanting to prove themselves or one who has never touched VFX before might not appreciate the effort required to make certain changes and the costs associated with it.
Here's a lesson - people are the worst people. ALL OF THEM. You, me, your best mates. Stick anybody in a creative situation and they will justify their position with pointless fixel-fuckery. This costs time and money if not reined in. With their long-established place in the greater entertainment industry threatened by the little places or those abroad in cheaper economies, studios really should learn to say 'No, we're not taking this. You asked for x and y. We allow you 2 changes. Here's x and y after 2 changes. You want more, pay more.'
Unfortunately I've seen situations where this caused clients to actually go elsewhere mid-project causing headaches all round as assets need passing to studios who use totally different software. So in this situation, the clients are costing themselves cash. That could happen if you're big, small, etc, and imo it's that fear of saying 'No' and 'Don't be stupid you pixel-fucking arse-fez,' that is adding to this work ethic of long days and cutting budgets again and again. It raises expectations of everybody.
Another contributor to cost is legacy pipelines imo. The smaller studios tend to have more flexibility around their workflow. A large team must be managed through a strict pipeline or else compositors don't know where to find the renders they need, the 3D team lose assets easier and so on.
Don't get me wrong. Every creative process has clients and inevitably their ideas and your don't always meet, but VFX is a business and many seem to forget that. In short, it takes a lot of people to create something like a Marvel film or a VFX-heavy TV or Netflix show, but that amount of people could be slashed dramatically if it weren't for hang-ups from the past and people being such people about everything.