Remember to compare hotels in similar market segments.
Budget - Motel 6, Econolodge, etc.
Midscale - Four Points, Hampton Inn, etc.
Upscale - Sheraton/westin, Hilton/Doubletree, etc. (this is really the tier you start seeing room service)
Luxury - St Regis/W/Luxury Collection, Conrad/Waldorf Astoria, etc.

Hilton offers roughly the same wifi as SPG. You either need to have status or stay at a "midscale" hotel to see free internet in rooms.