Problems with democracy - 2/3 vote requirements

One of the abuses of the democratic process that has become increasingly popular here in California is imposing 2/3 vote requirements to protect some vested interest. The abusive part of 2/3 vote requirements stems from the fact that typically a bare majority are imposing at 2/3 vote requirement on future voters. So if you have a particular viewpoint and can convince 51 voters out of a 100 current voters to vote your way in the future votes for your point of view equal 2 of the other sides votes. So if tomorrow 65 out of 100 want to vote the other way, they lose.

Now big business has recognized the extraordinary power of imposing 2/3 vote requirements. Proposition 16 on the June 2010 California ballot was an attempt by a private for profit energy company to protect their monopolies by imposing a 2/3 vote requirement on any public entity that wants to try to provide cheaper or greener energy to their citizen/voters. It was barely defeated.

Every government entity should have a rule that no law can impose a higher vote requirement on future voters than is achieved in enacting the law. So if 51% of the voters approve a particular law today, the law cannot impose any requirement higher than 51% approval on future voters.

Update:  Prop 26 on the November 2010 Ballot sought to impose a 2/3 vote requirement to make it harder to impose state or local fees and taxes.  It was approved by 52.5% v. 47.5%.   That was 52.5% of the 43.7% of the eligible voters who actually voted.

California Constitution Article II Section 2.5 provides that a voter who casts a vote...shall have that vote counted.  Doesn't that imply one group of voters cannot devalue the vote of other voters?