AWS is not going to enable S3 endpoints by default, and most of the thread is downvoting the correct explanations like thinking in terms of a small hobby VPC, not the architectures AWS actually has to support.

Why it should not be done:

1. It mutates routing. Gateway Endpoints inject prefix-list routes into selected route tables. Many VPCs have dozens of RTs for segmentation, TGW attachments, inspection subnets, EKS-managed RTs, shared services, etc. Auto-editing them risks breaking zero-trust boundaries and traffic-inspection paths.

2. It breaks IAM / S3 policies. Enterprises commonly rely on aws:sourceVpce, aws:SourceIp, Private Access Points, SCP conditions, and restrictive bucket policies. Auto-creating a VPCE would silently bypass or invalidate these controls.

3. It bypasses security boundaries. A Gateway Endpoint forces S3 traffic to bypass NAT, firewalls, IDS/IPS, egress proxies, VPC Lattice policies, and other mandatory inspection layers. This is a hard violation for regulated workloads.

4. Many VPCs must not access S3 at all. Air-gapped, regulated, OEM, partner-isolated, and inspection-only VPCs intentionally block S3. Auto-adding an endpoint would break designed isolation.

5. Private DNS changes behavior. With Private DNS enabled, S3 hostname resolution is overridden to use the VPCE instead of the public S3 endpoint. This can break debugging assumptions, routing analysis, and certain cross-account access patterns.

6. AWS does not assume intent. The VPC model is intentionally minimal. AWS does not auto-create IGWs, NATs, Interface Endpoints, or egress paths. Defaults must never rewrite user security boundaries.