The operating costs of a VLJ are still insanely huge. Example: a piston plane - SR22 can fly 200mph for 1200 miles on one tank of fuel. Approximate cost of that flight including amortised repair and maintenance costs: $1000. A VLJ, like SF50 can do that same flight at 320mph, but at an amortized cost of about $2600. Mostly it is due to engine overhaul costs. Overhauling a piston engine like in an SR22 is about $40k and done about every 2000 hours. Overhauling a jet like the in the SF50 is about $700k, and done every 4000 hours.

Until that comes down, jets will simply not approach uber-useful affordability for even people who buy full-fare first class seats.

(Fuel consumption is also much higher both in gal/h and in $/hr for jets compared to pistons)

And piston planes are not nearly as useful for air taxi due to them being unable to fly high enough to avoid most weather. Oh and in general turbines are an order of magnitude less likely to fail per hour.