Common refrain from my perspective. No wonder kids don't like fruit. It's bred to survive picking and transport with minimal damage, often seedless, and have as long a shelf life as possible while looking attractive. It's picked under-ripe by a big margin.
It tastes like shit. Pithy, flavorless, sour, etc. Some vegetables even fall into this trap. They're big, pretty, and pithy. Dry. Hard.
It's been a noticeable shift since I was a kid, and I was spoiled by growing up in a major fruit-growing area. Could pick up a flat of fresh strawberries for $6. Fresh melons, tree fruit, berries...all were available during the summer. Didn't have too much cooler-climate fruit like apples though. That fruit was better than candy many times.
I've been making an effort to try to locate as much fruit or whatever to grow ourselves that tastes right, looks be damned. It's a lot harder than I thought. Many of the seeds found at stores around this time of year are hybrids that often fall into the same commercial trap - big, showy, and shitty. You've got to go places like Seed Savers Exchange and buy the older varieties that are less fucked with.
Regarding vegetables: I don't know where you live, but at least in the United States there are tons of online seed stores selling heirloom produce, and a growing number selling open pollinated varieties at that. There are also quite a number of hybrids that aren't bred for industrial agriculture. I'm in a somewhat odd climate in the Pacific Northwest so I try to source seed locally because the varieties they sell often perform better here, but even then I have my choice of numerous seed companies.
Regarding fruit: agreed, fruit seeds can be really hard to source; most fruit is sold by the plant instead and variety options are extremely limited compared to vegetables (plus plant starts are so much more expensive than buying seeds, especially online because of shipping). I really hope that some of the companies doing great work in the vegetable seed field will start offering more fruit seeds, but unlike vegetables fruit tends to be perennial and more commonly utilizes complicating techniques like grafting so I don't know how viable this hope actually is.