Solid state may be inherently more reliable than the older mechanical systems, but cost reduction and further miniaturization often hurts reliability... systems are made to last between 60,000 - 100,000 miles and will fail (vibration, voltage spikes, etc.) shortly after that. You many not hear about those failures because for most owners, 60,000 miles is the end of the car's life and time to get a new car..
Where on Earth are you getting these numbers from? Most of the Toyota club I'm part of have cars with well over 250,000km on them, most of these cars frequent lapping days and/or AutoX. I've seen people starve their engines of oil during high speed corners and throw a con rod through the side of their block. I've seen spun bearings, broken transmissions, differentials turned into shrapnel, but I've never once seen an ECU fail. Hell people will replace damned near every mechanical component on the car without ever touching the ECU. Vibration doesn't hurt IC's and Voltage spikes are a non issue thanks to those fancy $2 plastic blades known as fuses.
And most of the rest of the message just complements what I am saying. The performance, by just about any criterion, of both vehicles sold to the common person and vehicles sold to enthusiasts has gone down, not up. Even the occasional engine 'upgrade' is more than offset by weight increases and other performance hindarences. The only real and measurable improvements to vehicles in modern-day has been up-to-date styling and higher profit margins.
Econoboxes are more powerful now than they ever were, just look at the lineage of the Civic if you think otherwise. A 1972 Civic 1200CVCC vs. a 2004 Civic Si. The 2004 will accellerate faster, brake harder, pollute less, get better mileage, have a lower drag coefficent, has more interior space, is safer and has a higher Top Speed than any Civic before it. The same goes for performance cars, while I love the Classic Z cars, pit one up against a 350Z on a track and watch what happens, the 350Z will walk all over it. Same goes for the Chevy Corvette, Porsche 911, Nissan Skyline GT-R and pretty much any other performance marque in the world. Sure the older ones may be lighter more and more tossable, but when it comes to real world performance, they are simply no match for their modern counterparts.
The only exception to this rule would be the massive V8s that were common in Yank cars of the 60's, but keep in mind that they were heavier than ANY modern car due to the fact that they had Full Frames rather than monocoque (unibody) chassis. Ever driven a classic Mustang or Camaro? They were relitavely lightweight compared to their muscle car bretheren, yet they have brakes that are practically unusable after two or three hard stops, little to no torsenal ridgidity, and horrible suspension (steel leaf springs). They were really only good at going fast in a straight line.
Anyhow, like I said, whoever is feeding you these 'facts' should really brush up and open their eyes.