Sure you can fly into them (if you have a suitable short field type). It is being based there that is hard to achieve. I tried this some years ago. No chance at all and the most straight and polite enquiries are met with a rebuff. Most of them are also very short - 500m or less.
It's not the future of GA - much as some may think so. It is the future of (mostly) brief short range bimbles which in terms of a long term "payback" for all the hassle involved in flying is a dead end.
The more intense club-type scenery is also not for people who have a life, a family, and a job; they want to come along and fly and not hang around much. The strip scene is not interested in those types. They want people who live their lives there - a bit like gliding clubs.
If GA ended up in farm strips, the pilot age demographic would shift a couple of decades nearer to the upper limit of male life expectancy than it already is
Sure there are exceptions but it's an uphill job against the Planning regs, so these will always be limited.