If you run a Plone site, you may find yourself envious of PHP WCM systems that are so easy to host on cheap, basic hosting plans. While many of the PHP based WCM products are designed to run on a shared hosting plan, most hosting providers don't even know what Zope is and don't want it on their servers. You may have been burned by the Zettai implosion and have been afraid to trust another Plone specialist. Maintaining a single instance of Zope on a leased server is not hard. You just need to know about packing the database and other administrative functions. The only hurdle is the need for basic server administration skills (monitoring, security, backups, etc.) that many small companies tend not to have... at least not to the level that you need.
Things may be about to change. Jarn (formerly Plone Solutions. They changed their name as part of the transfer of the Plone name to the Plone Foundation.) has published their framework for Plone hosting. From a technical perspective, this may be an even more generous move than changing there name. If hosting providers pick this up and use the technology as a way to expand their offering, Plone may see an adoption trend similar to what Mambo saw when it became installable through Plesk.
A Mambo-like growth spurt is probably too ambitious. Zope tends to need more resources (memory, in particular) than your average PHP based system that can run on a stingy VM or shared host. But still, there may be a noticeable increase in options. On the Plone hosting page, there are 6 providers (including Jarn). It will be interesting to see if this list expands as a result of Jarn's move.