As a successor, A. C. Gilbert, Jr. wasn't A. C. Sr. and did not pretend to be.
The materials I've read indicated that A.C. Gilbert Sr. ran the company until his death in 1961. Then Jr. took over the business. He was ill-prepared, but maybe the days of electric trains and erector sets were over anyway. According to Wikipedia, Jr. died in 1962, so he was at the helm less than two years.
I had a 1960's Gilbert Chemistry set, which I absolutely loved. But it was a strange arrangement with open backed plastic frames holding everything in slots. Four chemicals to an inseparable unit. So, while chemistry sets were popular at the time, a Gilbert one probably wasn't the best choice. My older brother had a Porter set that was of traditional construction. Don't know whether Lionel had purchased Porter by then.
Slot cars certainly were popular, Gilbert had some on the market, including a horse racing set. They also had a clever line of three rail track (one conductor in the slot), so two cars could operate independently in the same lane. But the sets were kind of crude, and didn't work as well as the Aurora HO sets. I think Strombecker had some good stuff too.
Lionel's HO slots appeared to be a knockoff of Atlas product. Their Standard line was originally Scaletrix imports. When they severed the relationship with Scaletrix, their own product was not very good.
