If you look back to Percival Baxter, as a lawyer, politician and governor it was obvious that he did not trust politicians as during and prior to his era, the legislature's biggest goal was to distribute public lands to private interests. He wanted to protect the lands at BSP "forever" and his biggest concern was that after his passing that despite his statement of his objectives in the Deeds of Trust, subsequent legislatures could do what they pleased under state control. He also realized the "power of the purse" and knew that if he did not set up a long term funding source to fund operations that the legislature could attempt to take control under the auspices of using public money to operate the park. He spent 50 plus years working to try to set up a special purpose entity that would be hard to break his deeds of trust and created and endowment that funds about 60% of the parks budget (the public funds the rest by road fees and user fees)
Fast forward a less than decade from his death and conservationists has the same issue that the legislature was beholden far more to commercial businesses than the general public when the concept of preserving Mt Bigelow rather than turning it into a ski resort. Maine voters used the referendum process to force Maine Government to establish the Bureau of Public lands to preserve land for Maines future. Funds generated by the lands stayed in the BPL budget to try to decouple legislatiuve control. Attempts were Maine to keep these lands managed for the Maine people and set a high hurdle to the legislature to contravene the peoples wishes. It lasted through several administrations until former Governor LePage forced the BPL to start cutting trees to increase revenue well over prior management limits and ordered the money to be handed back to the state which was contrary to the original legislation. The public's memory is fleeting and as exhibited by this transaction, the bureaucracy has a convenient memory when it comes to helping out politically connected businesses. This in on both sides of the aisle.
Luckily, this route is somewhat out of sight/out of mind, maybe some group will take up further strengthening state law but given current policies in Washington, its looking like the FERC is going to be given fast track rights to put in gas and power lines so this may not be the last New England power or gas line built by multinationals under the guise of public benefit. Now the big question is will Mass extend the contract completion date, given the potential for power issues this winter I expect they will sign in heartbeat.