In the course of navigating the labyrinthine world of software development, there are certain insights that come with experience, especially when dealing with PHP developers. In retrospect, I find that there are cardinal pieces of information that I wish I had known prior to my first PHP developer hiring experience.

The PHP language, originally conceived as "Personal Home Page", has evolved into a recursive acronym that stands for "PHP: Hypertext Preprocessor". PHP is an open-source, server-side scripting language that is principally applied in web development but is also utilized as a general-purpose programming language. PHP is embedded into HTML, which simplifies the process of writing pages that include scripts.

Firstly, it's crucial to understand that the PHP developer’s level of experience isn't exclusively defined by the number of years they have been working. A developer’s prowess and proficiency is often a function of their exposure to diverse projects, problem-solving skills, and their continuous learning ethos.

In the realm of mathematics, this can be likened to the concept of deep learning versus wide learning. A developer may have spent several years (depth) in the industry but within a restricted domain while another might have less calendar years but has worked on multifarious projects (width). The latter often brings a broader perspective and a more versatile skill set to the table.

Secondly, the developer's understanding of the MVC (Model-View-Controller) architecture is fundamentally important. MVC is a software design pattern that divides the related program logic into three interconnected elements, ensuring that the internal representations of information are separate from the ways information is presented to, and accepted from, the user. This architecture is commonly used for designing software that divides an application into three interconnected parts in order to separate internal representations of information from the ways that information is presented to and accepted from the user.

The developer's dexterity in handling this architecture often impacts the speed and efficiency of the development process, as well as the ability to effectively troubleshoot and maintain the software in the future.

Thirdly, consider their knowledge of PHP-based frameworks. Frameworks offer a basic structure for streamlining the development of web apps, such as Symfony, Laravel, CodeIgniter, and more. They automate the implementation of common solutions, reducing the volume of original code needed.

Using frameworks can be likened to the economic principle of division of labor. By automating the common tasks, developers can focus on the specific requirements of the web application, thereby increasing overall productivity and efficiency.

Last but not least, the developer's ability to optimize for performance is crucial. They should be adept at techniques such as caching, which is the process of storing retrievals in future requests to speed up subsequent data retrievals. This concept is similar to that of statistical regression to the mean, where a value is replaced by an average of a larger set of values to reduce the impact of extreme values.

Another technique is using content delivery networks (CDNs) which are systems of distributed servers that deliver pages and other web content to a user, based on the geographic locations of the user. These are vital concepts a PHP developer should be well versed with.

In conclusion, as with any hiring process, it is essential to look beyond the surface, challenging our implicit preconceptions, and focusing on the capacity for problem-solving, knowledge of modern techniques and tools, and a commitment to continual learning. Armed with this knowledge, the hiring process can be less of a gamble and more of a strategic, informed choice.