Blobs are formed only if you let them. Bleed your opponent early game and create a health crisis, forcing him to get an angulance. with 2xSturms and Kubels. A rushed Flak is surprisingly game changing against USF. Same start apllies against the Bris.
The SU can't blob and even if they do they're just making themselves a laughing stock.
SU can blob if he goes t1, gets an m3 and penals.
You lose the earlygame because of m3, su get munition to get flamers and mines.
Once you lost the map you have to spread your troops to cap back, but you get punished by either a giant flamermob, the m3 or maxim/dschk.
Atleast I cant think of any way to beat that and before I get the l2p card. I´ve seen much better players get steamrolled by this, for instance luvnest.
On topic:
The only thing to atleast make the blobber bleed is the ostwind, but you have to constantly babysit it and keep jaegers around it. Until there it´s pretty much a fight for survival.
A big enough usf blob with zookas can ohk it and even take out the schwerepanzerHQ without smoke or any kind of armour/artillery. 8cp is also realy late.
Without hmg it´s realy not easy to counter the blob and even if you get the mg34 it gets overrun, just a-move towards it. The flakhalftrack doesnt stop the blob either, it delays the first tank and dies to easily.
Imo it´s not impossible to beat blobs as okw, but it isn´t an easy task.