The first difference is the expertise level of the chemists who formulated the glue. Glue companies do not hang a "Chemist wanted, no experience needed, will train" sign on the door. Professional chemists spent years and years of their lives in colleges and universities studying the processes involved with formulating a substance. They understand glues down to the last molecule. A home chemist may have read a book, and thinks he knows all.
Another key difference is the type of equipment used. Glue company chemists have millions of dollars worth of equipment at their disposal. Some of the highly scientific equipment includes mass spectrometers, pressure testers and shear testers. Also, they have simulation rooms, where a glue joint is subjected to constant rain or to wide desert-to-arctic temperature variations. A home chemist has pots and pans and a stove.
All glues have to undergo final strength testing. This determines exactly what the glue is capable of. Strength testing usually involves stressing a glue joint until it breaks, and recording the breaking force. A woodworker developed one home glue testing device and used a bathroom scale to measure poundage. Commercial glue companies have highly accurate testing equipment, able to measure strength down to the last microgram. The level of sophistication of the testing equipment is also vastly different. For example, one professional glue tester has data outputs stored in a computer. A home brew chemist simply can't compete with the level of sophistication of the strength testing equipment.
Safety of the glue is another difference. Commercial glue companies understand their liability for the safety of their products. For example, a company might claim their glue is waterproof. Yet, a boat made with the glue could sink because the glue dissolved in the water, causing the loss of lives. For this reason, glue companies specifically state what their glues can and cannot be used on. A home brew chemist may not even think of the safety factors. Her main concern is developing a superstrong glue. The glue may be strong, but may dissolve in areas she didn't even think about, such as a high-altitude condition or a subzero temperature.