FWIW, when I asked my CFI about those options, I got a similar sort of response. It seems that the majority of the flight school industry is built around the ASEL PPL model, and a lot of CFIs (most?) and school administrative people honestly don't know much about the other options.
This extends to their fleets, as well - they tend to build around C172s and PA28s (at least from my experience).
That makes sense from a historical standpoint, but there are a couple of things I'm discovering probably because I'm just getting into this now, not 5+ years ago. One is that the costs to learn and especially the costs to fly have skyrocketed in the past few years.
A second is that there's this growing pilot shortage and a lot of places are shifting their focus to people who want to go from zero to ATC-rated and off-to-the-Majors ASAP. Lining up 10-20 such students a year represents a very solid business strategy. But the flip side is they're not making much effort to cater to "weekend warriors" who are just looking to fly occasionally and particularly aren't looking to make a career out of this. (There's one guy who makes lots of YT videos where he told someone very frankly that he has a large backlog of student inquiries, but is only focusing on those who are looking at it as a career move. I can't imagine he's alone given the current pilot shortage.)
But one way some places are tackling the cost issue is they're beginning to invest in LSA aircraft. I'm guessing that if you're looking at a 40-50 year-old aircraft and thinking about replacing the avionics with something more contemporary, it's around $40k investment. I'd be thinking it might be wiser to just get a new (or much newer) aircraft already equipped with what's needed, and LSAs tend to be less expensive than their slightly bigger/faster/heavier siblings.
However, another thing I've heard lately is a lot of talk about statistics that show around 85% of people who begin working on their PPL don't complete it, mainly because of COSTS. If you're looking to get into this as a career, then there are some fairly predictable steps you can take to ensure you're making money from this at some point. But simply getting a PPL is little more than "an expensive hobby" that a lot of people find hard to justify.
So maybe by starting with something that's 1/2 or 1/4 the time and cost of a PPL would get new students soloing much faster and then they'd become long-term customers instead of dead-end students. Especially if you're already leaning towards bringing in some newer LSA aircraft into the stable.
Also, all of this is hanging under the shadow of MOSAIC that may well end up recategorizing (?) a lot of GA aircraft as LSA and available to people with Sport Pilot licenses. I mean ... what if your entire fleet was suddenly eligible to be flown by Sport Pilots? I'd bet a lot of schools will start tripping over themselves to start offering Sport Pilot certifications ASAP! But that's just the way I tend to think.
This industry seems to be a very conservative bunch and dominated by older folks with decades of experience, most of whom move as a herd. They're skeptical, don't like change, and prefer that others run out ahead so they can see what sorts of arrows the took when the come back.
Nothing wrong with that, for sure. People get that way as as they age. But it's the younger folks who tend to be more willing to look at jumping on obvious business trends.