I was unaware of the literal meaning of "fee simple" as "zero rent."  Interesting.  I'm not familiar with Canadian land law, but in the US a fee simple estate or a fee simple absolute interest is absolute ownership in perpetuity subject only to taxation, the police power (zoning, etc.) eminent domain and escheat (if an owner dies without heirs land reverts to the sovereign).  The US constitution is very clear that eminent domain requires "just compensation" typically at market value.  It can be debated how "open" or "fair" that market value is because the seller need not be willing and the sovereign is an a position of control, but that's another matter. If the sovereign wants the land back it has to pay for it.

Does eminent domain have a different interpretation in Canada?

Fee simple at limitation and fee simple conditional estates may terminate under particular conditions which presumably would have made them less valuable in the market than the fee simple absolute.

Scott Cullen