If somebody had half a brain, the industry know-how and financial backing, I think it could be revived. So many people are absolutely nuts about anything Mid-Century Modern, and those orange-roofed HoJos are about as Mid-Century Modern as you can get. So many people have good memories associated with them, the bad years of decline can be overcome. Keep the good (those fried clams, etc.), bring in fitting modern menu items that fit the theme, lose the bad, find a cool way to cater to the hipsters and moneyed older people who love the style. Put in a full service bar.
The last one here in my area was semi-attached to a high rise Howard Johnsons hotel. The HoJo restaurant building became a Hooter’s and still is to my knowledge. The hotel is under another name. That whole area was once very popular and very busy, but has gone downhill as the big mall across the way went downhill.
Sounds like the place where I grew up ... The HoJo Restaurant is still there in form, but it has another name now, and the Orange roof is wood shingle now.