The 737-500 is decades-old, a full two generations before the MAX, with technology that, in some ways, hearkens back more to the early days of the "jet age" than to anything in modern aircraft. And it doesn't have the MCAS system that caused problems with the MAX.
Frankly, when you get a crash involving a twenty-seven-year-old aircraft that has likely made tens of thousands of flights covering millions of miles, the most reasonable things to look at are pilot error and inadequate maintenance, not some inherent design or manufacturing flaw of the aircraft type that somehow escaped detection for decades.
At the risk of making an analogy that unavoidably trivializes the tragedy of this event, if your brand-new Honda Accord has its transmission self-destruct within the first year of ownership, you might suspect a manufacturing problem; if the same thing happens to the transmission of your 1995 Accord with 600,000 miles on it, you're probably not going to be demanding that Honda issue a recall; rather, you might want to ask yourself if you kept up-to-date on the fluid changes and other maintenance for the unit. Apparently, the airline in question here has a pretty bad reputation among Asian carriers, to the point that even one of its own executives, at one point, suggested the airline be grounded until it had worked out its maintenance problems.