Yes, ad hoc networks are more efficient for wireless-to-wireless communication for the reason you mentioned. In ad hoc networks (which are technically called "IBSS" networks), devices talk to each other directly.
Contrast a typical infrastructure network with an AP, where the AP retransmits every wireless-to-wireless transmission (that is, performs "intra-BSS relay") in order to avoid the "hidden node problem". This retransmitting can effectively cut your wireless bandwidth in half when two wireless devices are talking to each other.
No one does intra-BSS relay in IBSS (ad hoc) networks, not even the originator of the IBSS. Originators have no special responsibilities at all in an IBSS network. Once other devices join, they are all fully equal peers.
As for range, the range of typical consumer indoor Wi-Fi devices is given as "up to" 150 feet, not 30 feet. If you have a device that lists its IBSS range as 30 feet, then maybe it uses lower transmit power in IBSS mode, limiting its range. In an IBSS, the range is measured between every possible two-device pairing. That is, "up to" 150 feet becomes the diameter of your network, whereas in an infrastructure network with an AP doing intra-BSS relay, "up to" 150 feet would have been just the radius, giving you a diameter of "up to" 300 feet.
Mesh networks, as standardized by 802.11s, are a whole different thing. 802.11s is where generally your network infrastructure boxes figure out who to create wireless backhaul networks (kind of like self-configued WDS links) between themselves, while each box also typically provides local AP service to local clients. I don't know of any laptops or handhelds or printers or other consumer wireless clients that do 802.11s. It's usually something that only wireless-ISP-provided 802.11 infrastructure boxes do.