Not all customers do. Professional contracts and people asking special stuff or modifying their (Telenet-managed) firewall settings automatically get one. Other consumers - which is the large part of their customer base - get IPv6 with CGN/NAT64 with maximum 16 clients NAT'ed behind a public IPv4 address for legal wiretap+privacy reasons.

Really? I've never seen anyone with a shared IPv4. Maybe because every time I look into it the first thing I do is modify their firewall settings slightly. Heh.