Why are VPNs no longer free?

I'm curious to understand why VPNs, which were once commonly offered for free, are no longer available without a cost. Was there a shift in the market dynamics that led to this change? Did the increased demand for privacy and anonymity drive up the costs of maintaining VPN servers and networks? Or were there regulatory changes that impacted the availability of free VPN services? I'm eager to learn more about the reasons behind this transition and how it has impacted users seeking to protect their online privacy.