Yeah, they're definitely way too dim and way too small even by the standards of the 1960s. Minimum allowable lit area of the front turn signal is 22 square cm (3.4 square inches).
Here's the thing: all vehicle exterior lighting functions, even the ones that aren't mandatory (like daytime running lights and side turn signal repeaters in the USA, or central brake lights on cars made before 1986, etc) are highly specified as to their design, construction, numerous aspects of performance, durability, etc. It's far, far more detailed than just "Well, it's a red light facing rearward that comes on when I step on the brake, so it's a brake light" or "Well, it's amber and it blinks, so it's a turn signal" or "Well, the eBay ad said tail light, so that's what it is", etc. We do not get to just declare any ol' light into whatever function we want -- doing so is unsafe, even if we don't have to pass an inspection. This stuff matters if we want to keep the car (i.e., not get hit in traffic).
Double-whammy in this case: front turn signals mounted within 4" of the headlamp (or the low beam, on a 4-lamp system) have a minimum intensity requirement 2.5× the requirement for turn signals located farther away from the headlamps. That's so turn signals mounted close to the headlamps can still be seen at night with the headlamps on.
(also not "Well, if it's good enough on a motorcycle, then it's fine on a car" -- motorcycle requirements are way smaller/dimmer than car requirements).
There's probably an easy and inexpensive way to have good front turn signals with an appearance you can live with. How much height do you have between top of bumper and lower edge of that ridge where your present turn signals are located?
