I am pretty sure, as stated, that more expensive wetsuits can of course last longer, but not necessarily.
They are a lot warmer though, no doubt at all.
We live in a climate surfing in shorts only in summer, and having thick winter wetsuits in the winter with snow and ice.
So having used all kinds of wetsuits, shorts, shorts+neotop, 1-2 mm shorty, 2 mm shorty, 3 mm shorty, shortarmed 3/2, full suit 3/2, full suit 5/3 or 5/4 or 6/4, and occasionally drysuits.
Riding over 300 sessions per year (a lot, I know)
Summer shorty suits does not need to be very warm, just comfortable and fast to get in/out of.
But for the full suits, in particular 5/3 or 5/4, they will only be warm for 2 years, and then begin to degrade - this goes for ALL types and price classes.
So on the 3rd year you can definitely feel it begins to get colder, and on the 4th year most around here buy a new one.
I have had a short armed summersuit for more than 10 years, used a lot when in capetown, and in the summer around here, on colder days.
Not much warmth left, but it did its toll, and has been replaced now.
Other suits might last one season only, if a thinner shorty not that costly.
Others can last forever, literally, if a 3 mm and good quality.
But it is not that easy to know which will last, as an expensive thin super flexible might not last long, even if sewings are top.
And a stiff 3 mm might last what feels forever.
I never clean or rinse my suits though, this might mean they last longer, as it will be hard on any suit, and a complete waste of time IMO, and now you have to dry the suit also?
But others do rinse, I know, and they still lose their warmth after the second year of use.
As you use a low cost shorty, you could just replace it when worn as you do now, but if you want it to last longer, I would go for some not made out of the flexible neoprene, but either less flexible, or with thicker lining (less flexible also).