Is the next prime number always the next number divisible by the current prime number, except for any numbers previously divisible by primes?

Yes. First let me clarify what you are trying to say. Suppose we have a prime number $p$, and consider the smallest integer $n$ greater than $p^2$ which is a multiple of $p$ but which is not divisible by any prime less than $p$. The pattern you are observing is then that $n/p$ is the smallest prime number greater than $p$.

This is indeed true in general. To prove it, note that the multiples of $p$ are just numbers of the form $ap$ where $a$ is an integer. So in finding the smallest such multiple $n$ which is not divisible by any primes less than $p$, you are just finding the smallest integer $a>p$ which is not divisible by any prime less than $p$ and setting $n=ap$. Every prime factor of this $a$ is greater than or equal to $p$. Let us first suppose that $a$ has a prime factor $q$ which is greater than $p$. Then by minimality of $a$, we must have $a=q$ (otherwise $q$ would be a smaller candidate for $a$). Moreover, by minimality $a$ must be the smallest prime greater than $p$ (any smaller such prime would be a smaller candidate for $a$). So, $a=n/p$ is indeed the smallest prime greater than $p$.

The remaining case is that $a$ has no prime factors greater than $p$, which means $p$ is its only prime factor. That is, $a$ is a power of $p$. Then $a\geq p^2$ (and in fact $a=p^2$ by minimality). As before, $a$ must be less than any prime greater than $p$ by minimality. This means there are no prime numbers $q$ such that $p<q<p^2$. However, this is impossible, for instance by Bertrand's postulate (or see There is a prime between $n$ and $n^2$, without Bertrand for a simpler direct proof).

Think of it this way. Let $p_k$ be the $k$ prime. Let $n$ be the first composite number greater than $p_k$ so that $n$ is not divisible by $p_1,..., p_{k-1}$.

Claim: $n = p_k\cdot p_{k+1}$.

Pf:

What else could it be? $n$ must have a prime factors. And those prime factor must be greater the $p_{k+1}$. The smallest number with at least two prime factors all bigger than $p_{k-1}$ must be $p_{k}\cdot p_{k+1}$ because $p_k, p_{k+1}$ are the smallest choices for prime factors and the fewer prime factors the smaller the number will be.

so $n= p_kp_{k+1}$ IF $n$ has at least two prime factors.

So if $n\ne p_kp_{k+1}$ then 1) $n \le p_kp_{k+1}$ and 2) $n$ has only one prime factor so $n=q^m$ for some prime $q$ and integer $m$.

If so, then $q \ge p_{k+1}$ then $q^m \ge p_{k+1}^m\ge p_{k+1}^2 > p_k*p_{k+1}$ which is a contradiction so $q= p_k$ and $n = p_k^m > p_k^2$. As $n$ is the smallest possible number, $n = p_k^3$ and $p_k^3 < p_k*p_{k+1}$.

That would mean $p_k^2 < p_{k+1}$.

This is impossible by Bertrands postulate.

So indeed the next composite number not divisible by $p_1,..., p_{k-1}$ larger than $p_k^2$ is $p_kp_{k+1}$.